Reporting Requirements for Cooling Towers

Online comments: 17

• Ron F

  I appreciate the City’s commitment to protecting public health. However, I respectfully oppose the proposed amendment to require monthly Legionella testing of cooling towers (replacing the current 90-day requirement). This amendment is unnecessary, unsupported by evidence, and will impose undue financial burdens on property owners — especially residents of cooperatives and other multi-family buildings — without a proportionate public health benefit.

  1. Current Regulatory Framework Already Includes Frequent Monitoring and Maintenance

  Under existing NYC and New York State regulations, cooling towers are already subject to comprehensive oversight:

  Quarterly (every 90 days) Legionella sampling is required while towers are in use, and all sampling must be performed by certified laboratories.

  Owners must perform weekly heterotrophic bacteria sampling and routine system monitoring (e.g., water quality measurements multiple times per week), daily biocide treatment, and at least semiannual cleaning/disinfection events.
  These multi-layered requirements already serve to identify and control conditions conducive to bacterial growth before they escalate into outbreaks.

  The regulatory approach applied in NYC is already more stringent than many other jurisdictions (which typically require Legionella culture testing only quarterly while also emphasizing maintenance and water chemistry controls).

  2. Monthly Testing is Not Proportional to the Scientific Evidence on Legionella Risk

  Legionella bacteria are naturally present in the environment, and detection in cooling tower water does not necessarily mean that disease transmission will occur. In fact, many cooling towers test positive for Legionella at times without resulting in illness.

  Additionally:

  Legionnaires’ disease outbreaks are relatively rare events given the large number of cooling towers and the existing regulatory framework in place.

  The most widely referenced industry standards (e.g., ASHRAE 188) and many state programs do not require monthly culture testing as a baseline frequency — they focus on maintenance, water quality control, and reacting to conditions that promote growth rather than a rigid monthly test schedule.

  The City Council’s rationale for the more frequent testing is linked to a recent outbreak; but that outbreak — while tragic — was linked to failures in maintenance and remediation after positive tests, not necessarily to the testing interval itself. Furthermore, existing rules already require remediation and reporting upon positive results.

  3. Significant Financial Burdens on Property Owners and Residents

  Monthly Legionella testing will impose material new costs on buildings with cooling towers. These tests must be conducted by or under supervision of qualified professionals and submitted through certified laboratories.

  For cooperative boards and other residential property owners, increased testing costs will likely translate directly into higher maintenance fees, assessments, or rents at a time when affordability in NYC is already a critical concern. Many co-ops operate on thin financial margins, and increased mandatory testing could disproportionately affect seniors, low-income residents, and others struggling with the high cost of living in the city.

  The amendment’s financial burden falls on property owners rather than on operational factors that actually contribute to Legionella risk. A more targeted approach that focuses on maintenance compliance, enforcement of existing requirements, and better support for small property owners would be more equitable and effective.

  4. Alternative Strategies Can Better Balance Public Health and Economic Impact

  Instead of strictly mandating monthly testing, the City could consider:

  Enhanced enforcement of existing maintenance and inspection requirements to ensure that quarterly tests are meaningful and that positive findings are acted on promptly.

  Targeted testing protocols for buildings with known risk factors or prior violations rather than a blanket monthly requirement for all.

  Subsidized testing programs or technical support for small residential buildings to help them comply without undue financial strain.

  This approach would preserve public health protections without imposing unnecessary costs on owners and residents.

  Comment added February 12, 2026 11:21am

• Anonymous

  We already have excessive testing requirements which puts an extreme burden on property owners and whoever they pass their expenses onto. If you are following what is in place already, there should be no issues. We keep hearing about making this city more affordable while policies like this do the complete opposite.

  Comment added February 12, 2026 3:36pm

• Mitch Kaufman

  I really wish we could all focus on the time of the year when we are most at risk. Many cooling towers run 12 months per year. Of those towers, most operate in what is known as “free cooling mode.” Condenser water temperatures are as low as 40 degrees F. This is a temperature where the legionella bacteria do not thrive. Any cells that get into the atmosphere through misting are immediately killed by the ambient temperature of the atmosphere. Let’s focus on the summer months when condenser water temperatures are higher and where bacteria thrive. It is that time when these outbreaks occur.

  Let’s also consider what overexposure to chlorine does to equipment and to the environment.

  Comment added February 14, 2026 12:15pm

• Jack Glass, CIH - ALC Environmental

  The current version of this rule requires a certified laboratory to collect the samples. This is not a viable requirement due to the fact that nearly all laboratories only provide laboratory services. Currently, sample collection is performed by a large number of environmental consultants who also provide additional services at the site, such as inspection and disinfection.

  We strongly recommend changing the wording to: Sampling shall be conducted by firms and/or individuals experienced in the collection and management of environmental samples.

  Comment added February 18, 2026 11:09am

• Abraham Cullom

  1. The proposed rule defines startup as putting one or more cooling tower systems or components into operation. Cooling tower system components are then defined broadly and include pumps, filtration devices, chemical controllers, metering pumps, and other wetted equipment. Because some of these components may operate intermittently during normal operation, the current definitions could classify routine operational adjustments as system startups. The Department may wish to clarify that “startup” refers to placing a cooling tower system, tower cell, or circulation loop into operation following shutdown, commissioning, or extended inactivity, rather than activation of individual ancillary components.

  2. The proposed rule requires manual monitoring of disinfectant residual three times per day when bacteriological indicator results exceed the specified threshold, but “manual monitoring” is not defined. As written, the requirement could be satisfied by taking multiple measurements in rapid succession following a biocide addition, which may not demonstrate sustained treatment control. In addition, three monitoring events per day may be operationally burdensome for water treaters who service sites periodically rather than maintaining continuous on-site presence. Defining manual monitoring and clarifying a procedure that captures representative system operating conditions would improve implementation. Also, the HPC retesting requirement appears to provide a minimum waiting period, but not a maximum.

  3. The proposed changes close what I felt was the most important loophole in the previous version. Namely, that summertime hyperhalogenation Legionella samples could be counted as the quarterly sample for the summer. In practice, this meant that there was less known about Legionella growth in a tower during normal operating conditions in the most critical period of the year. The monthly testing requirements, at least during the summer, ameliorate this situation. If it is the intention that Legionella tests for hyperhalogentation can still serve for the routine monitoring sample, this should be clarified. If not, the sequence and spacing of samples should be clarified.

  Comment added March 4, 2026 11:02am

• Anonymous

  1. Can the Department provide a definition and example of a valve schedule with the required elements?

  2. Confirm “Compliance Inspections” of cooling systems remain at the frequency of every 90 days.

  3. Recommend that Table 8-1 include the hyperhalogenating instructions listed in Paragraph (5) of subdivision (f) of Chapter 8-05 as a footnote or within the Process column of the table.

  4. Define “manual monitoring” referenced in Table 8-1.

  5. Edit Table 8-2, Level 2 Response, second paragraph to include the words “for bacteriological indicator” after retest water to be clear on the type of retest.

  Comment added March 10, 2026 10:25am

• Carson Riggins

  I would like to thank the city for their commitment to prioritizing public health. I would also like to thank the city for the opportunity to comment and make my thoughts known on this proposed rule.

  I believe that requiring testing every 31 days is too frequent and has diminishing returns. The Department of Veterans Affairs has a guideline for testing for legionella bacteria in VHA buildings (Department of Veterans Affairs Directive 1061(4) Appendix D Section 4). This guideline calls for testing for cooling towers within 7 days of startup, and then quarterly testing of legionella bacteria in VHA buildings, which as I understand are usually healthcare settings. If the VA is only recommending testing every 90 days* for a healthcare facility, I find it unconvincing that the frequency for everyday New Yorkers needs to be increased to every 31 days.

  Thank you for considering my comment.

  Carson Riggins
  *Not including the first startup test
  Also please see attached a pdf copy of the VA Guidelines

  Comment attachment
  10614_D_2021-02-16.pdf

  Comment added March 10, 2026 4:43pm

• NYC-CTIS: NYC Cooling Tower Inspections & Services

  Regarding the proposed amendments to NYC Cooling Tower Regulations, we fully support measures that enhance oversight and improve public safety. At the same time, we respectfully raise a few concerns and hope the DOHMH will consider our specialized expertise in water treatment, consulting, and water safety when finalizing these updates.

  1. Key Requirement Considerations

  Annual certifications must be conducted by an independent third-party environmental consultant, (certifying vendor must not have any existing legal affiliation with the current water treatment vendor in care of the building).

  IMPORTANT RULE
  The third-party certifying agency (independent environmental consultant) must not have any existing legal affiliation with the building’s current water treatment vendor.

  REASON
  
Similar to elevator annual inspections (NYC Administrative Code 28-304), those inspections must be performed by a third-party agency not the company that performs the maintenance.

  POLICY LOGIC
  Third-Party Independent certifications prevent:
  self-certification bias
  falsified compliance
  underreported deficiencies

  2. Key Requirement Considerations

  Third-party independent inspections are required when Legionella levels reach Level 3 or higher. An independent environmental consultant would verify that the water treatment equipment is operational, confirm that the corrective action has taken place in accordance with the MPP, and collects a legionella sample; sampling will continue until Level 1 or below is achieved.

  IMPORTANT RULE
  The third-party certifying agency (independent environmental consultant) must not have any existing legal affiliation with the building’s current water treatment vendor.

  REASON
  
When a cooling tower is identified as having an elevated Legionella risk (Level 3 or Level 4), Heightened Monitoring of that system should be implemented to safeguard public health. For example, the NYC DOHMH frequently requires a Heightened Monitoring Plan (HMP) when a cooling tower or building water system shows evidence of increased Legionella risk.

  Policy Logic
  Third-Party Independent Inspections:
  Elevated Legionella levels (Level 3 or Level 4) indicate a higher risk to public health.
  Independent inspections ensure that corrective actions are verified objectively, eliminating potential conflicts of interest from vendors reviewing their own work.
  This policy mirrors the Heightened Monitoring Plan (HMP) process typically requested by NYC DOHMH, which is designed to implement more rigorous oversight for systems posing elevated Legionella risk.
  Continuous sampling and verification until Level 1 or below ensures that the system has returned to a safe operating condition, maintaining compliance and protecting building occupants.

  3. Key Requirement Considerations

  For an elevated bacteriological sample/dip-slide (over 10,000), the management and maintenance team must initiate monitoring of disinfectant residual one time per day until water treatment achieves a target biocide residual between the range of 1-3 PPM for two consecutive days.If two (2) consecutive days are not achieved within 3 days, collect a Legionella sample and continue to adjust. ORP data from a smart water treatment controller will meet the above noted requirement.

  IMPORTANT RULE
  For cooling tower water systems, the typical target free chlorine residual is guided by standard industry practices. While ASHRAE 188 does not specify a fixed ppm, most industry practice interprets a free chlorine residual range from 1-3 PPM as a typical operational target to prevent bacterial growth.

  REASON/POLICY LOGIC
  Daily monitoring over two consecutive days provides sufficient time to respond to elevated bacterial counts and confirm that the system maintains a sustained disinfectant residual within the recommended range. Maintaining 1–3 ppm free chlorine helps ensure effective disinfection, reduces the risk of Legionella growth, and provides a clear, verifiable indicator of system safety consistent with standard industry practices.

  REQUEST FOR CLARIFICATION
  Regarding Violation 24 RCNY §8-06(b)(2), which states that a sample must be collected prior to cooling tower start-up. This appears to conflict with Page 11, Section 25(b)(2), which requires sampling within 3–14 days after start-up. It also creates confusion with the current definition of “start-up,” which considers a system operational once water is present in the system.

  Comment attachment
  NYC-CTIS-2026-DOHMH-COMMENTS.pdf

  Comment added March 10, 2026 5:26pm

• EJD CWT NYC

  Subject: Public Comment on Proposed Changes to NYC Local Law 159 of 2025
  To the Relevant Agency / Rulemaking Committee:
  Below is a summary of my comments and concerns regarding the proposed changes under Local Law 159 of 2025. As an engineering and water treatment professional with over 40 years of experience, I share the common goal of all stakeholders—the public, building owners, operators, and water treatment professionals—in ensuring safe and well-maintained cooling tower systems. We all want effective, streamlined regulations that protect public health while recognizing the practical realities of facility management.
  Based on my professional experience, I urge the city to consider the following points:
  Implementation Timeline
  The proposed changes are to take effect on May 7th, yet the definitive version of the law and its associated rules remain incomplete. This leaves building owners and operators with less than six weeks to fully rewrite their maintenance programs and achieve compliance. This is a highly impractical timeline for an industry-wide transition.
  Risk Analysis and Scientific Basis
  I respectfully request to see the city’s risk analysis justifying these latest changes. How has the city concluded that the public would benefit tangibly? Building owners already possess the highest incentive to maintain zero Legionella counts to protect their occupants and limit liability.
  Furthermore, data from the CDC indicates that potable water systems, particularly in hospitals, are the primary source of most Legionnaires’ disease outbreaks. Outbreaks stemming directly from cooling towers are a much rarer occurrence. It is also well documented that Cooling towers are only a small part of the problem. Cooling towers were identified as the source in 22% of cases. Our goal is not to address the other sources at this time, except to mention they account for 78% of outbreaks.
  Winter Risk Assessment for Cooling Systems
  The risk of a Legionella outbreak is lower during winter months. But the city does not adjust its risk analysis or its requirements.
  Environmental Factors in Winter-
  In colder months, factors naturally inhibit the spread of bacteria and reduce the need for testing.
  • Lower Temperatures: Cooling towers operate at lower water temperatures, often staying below the high-concern threshold of 77°F (25°C) cited by the CDC.
  • Reduced Aerosolization: Cooling tower fans typically operate at reduced speeds or in the off position. This results in significantly smaller or non-existent drift plumes (where the bacteria could be) compared to peak summer operations.
  • Seasonal Trends: CDC data confirms that most outbreak investigations peak in the summer and early fall when ambient temperatures are highest.
  • Organic matter: It is typically lower in cooler weather.
  • Windows Barrier. Cooling towers are located outside, and individuals typically keep windows closed in cooler temperatures. This forms a barrier from cooling tower plumes.
  Cause of outbreaks-All sources: The Risk of Process and Human Failure
  The Results of CDC investigations are below for the cause of legionella outbreaks.
  • 65% Process Failure: Breakdown in the established water management plan, i.e. No water “Plan” or not complying with the plan.
  • 52% Human Error: Lapses in manual treatments or inspections.
  • 35% Equipment Failure: Mechanical issues with pumps or sensors.
  • 35% Unmanaged External Change: Unexpected shifts in water supply or environment
  It is worth noting that “insufficient testing of legionella did not make the list” is often not the hidden culprit behind these outbreaks. One can conclude that creating and strictly adhering to maintenance plans supported by well-trained operators and properly maintained equipment—is the most effective path to minimizing risk.
  All these preventive measures are already addressed and mandated under current law. Specifically, performing weekly bacteriological dipslides, weekly inspection and monitoring water parameters three times per week will reliably detect issues, provided these tasks are being completed. The rapid mitigation of detected issues remains the most critical step in preventing an outbreak.
  Environmental and Infrastructure Impact
  Has the city conducted studies on the environmental consequences of these new rules? Specifically, what impact will the mandated increase in biocide usage have on local wastewater treatment plants and the surrounding environment? It is a well-documented engineering reality that the increased use of halogen-based biocides accelerates corrosion and significantly reduces the lifespan of expensive cooling equipment.
  Outbreak Investigations and Geographic Disparities
  I also have questions regarding the data driving these regulations, specifically the two outbreaks linked to the cooling towers at Harlem Hospital. As referenced in the NYC Health Department press release, it is highly unlikely that Legionella amplified to dangerous levels in that system in less than 30 days. https://www.nyc.gov/site/doh/about/press/pr2025/health-department-closes-investigation-central-harlem-legionnaires-cluster.page
  Because this event seemingly triggered the new regulatory changes, I request that the city provide detailed information regarding its investigation into these past outbreaks, including the actual Legionella levels recorded in the tower. Furthermore:
  • How will these new changes address the specific areas where past laws and city attempts have fallen short?
  • Why have these outbreaks been localized in Central Harlem and the South Bronx?
  Industry Literature and Expert Consensus
  The water treatment industry has previously raised concerns about the efficacy of these types of localized regulations. In the Summer 2016 issue of the Cooling Technology Institute (CTI) Journal, Sarah Ferrari published an article titled “New York Legionella Regulations: Are They Missing The Boat?” (page 60).
  https://assets.speakcdn.com/assets/2793/2016summerjournalcti.pdf
  After reviewing the data, she concluded: “Ultimately a case is made that these new regulations will not have a measurable impact on reducing the incidence of Legionellosis.” It appears she was correct.
  Conclusion I urge the city to reconsider the implementation timeline and the scientific basis for these amendments. Effective laws must be driven by accurate, holistic risk assessments rather than reactionary measures.
  Thank you for your time, consideration, and dedication to public health.
  Sincerely,
  EJD CWT NYC
  Certified Water Technologist
  Chemical engineer

  Comment added March 12, 2026 1:54pm

• Aaron Kassaw - President of LIMS Analytics Group, LLC

  To the Honorable Members of the New York City Council and the Department of Health and Mental Hygiene (DOHMH),

  We write to you today regarding the proposed amendments to Chapter 8 of Title 24 of the Rules of the City of New York, following the passage of Local Law 159 of 2025. While the common goal of all stakeholders is a safer New York, the current shift from a 90-day to a 31-day testing cycle has sparked significant concern among property owners, engineers, and environmental consultants.

  We respectfully submit that the most effective way to modernize Legionella prevention is not simply to increase the frequency of data collection, but to standardize and centralize how that data is managed.

  1. The Need for “Precision Safety” over “Maximum Testing”
  Blanket monthly mandates often ignore the operational science of cooling systems. In the colder months (October–April), many towers operate at temperatures that naturally inhibit bacterial growth. Mandating the same testing frequency year-round leads to:

  Diminishing Returns: The Department of Veterans Affairs (VA) maintains a quarterly standard for high-risk healthcare facilities; a monthly mandate for standard residential co-ops is statistically disproportionate.

  Unnecessary Costs: For co-ops and multi-family buildings on thin margins, these costs represent a significant burden that will be passed on to residents.

  2. Digital Accountability: A New Standard for Oversight
  Instead of a purely frequency-based approach, the City should focus on ease of accountability. We propose the creation of a Centralized City-Wide Water Safety Portal designed for real-time compliance. This system would function as the “digital backbone” of the City’s public health effort:

  Stakeholder: Water Treaters
  Role in the Digital System: Direct input of daily biocide levels and weekly inspections via a standardized mobile app.
  System Benefit: Replaces manual, fragmented logs with a verifiable digital trail.

  Stakeholder: Certified Labs
  Role in the Digital System: Automated API reporting of Legionella culture results directly to the City portal.
  System Benefit: Eliminates reporting delays and ensures the DOHMH sees positive results instantly.

  Stakeholder: City Auditors
  Role in the Digital System: Remote access to building “health scores” and maintenance logs without physical site visits.
  System Benefit: Allows for targeted inspections of “red-flagged” buildings instead of random audits.

  3. Incentivizing Compliance
  By creating a common system where results are reported directly by the labs, the City removes the “human error” and “self-reporting bias” that contribute to 65% of process failures during outbreaks. Furthermore, if a building can demonstrate a perfect “digital health score” through consistent biocide residuals and quarterly negatives, the City could allow them to remain on a 90-day cycle, while mandating monthly tests only for buildings with a history of non-compliance.

  Conclusion
  We urge the Council and DOHMH to utilize the upcoming March 16, 2026 Public Hearing to explore these technological solutions. Public safety is better protected by a system that makes it impossible to hide a failure than by one that simply generates more paperwork for compliant owners.

  Our established framework for the City of New York demonstrates a clear fiscal reality: the investment in proactive prevention is a mere fraction of the cost of litigation.

  Rather than navigating a labyrinth of burdensome regulations, we invite you to leverage our decades of expertise to centralize and streamline your entire compliance portfolio.

  Comment added March 13, 2026 10:18am

• ANONYMOUS

  One area of concern relates to the absence of a clearly defined standard governing the procedures used by the Department of Health and Mental Hygiene (DOHMH) during random testing or inspections. Currently, there appears to be limited transparency regarding the precise methodologies used when DOH representatives conduct a random sampling or field assessments.

  In the interest of ensuring that regulatory oversight produces meaningful and actionable outcomes, greater procedural clarity is necessary. When sampling results exceed permissible Legionella thresholds, it would be beneficial for the Department of Health to provide a comprehensive laboratory report accompanying the findings. At present, exceedance notifications may not always include the level of technical detail necessary for operators to fully evaluate the result and implement targeted corrective actions. A detailed laboratory report—including organism quantification, testing methodology, detection limits, sample conditions, laboratory accreditation information, as well as photographic images of the sample collected with the; location, date, time and when tested—would provide licensed RMO’s and water treatment professionals with the data required to make informed operational decisions.

  Providing this level of transparency would not only improve the technical quality of responses to exceedances but would also foster greater collaboration between regulatory agencies and facility operators. Ultimately, Legionella risk management is most effective when oversight, engineering practice, and scientific data work together within a clearly defined and consistent framework.

  In summary, while Chapter 8 of Title 24 and Local Law 159 reflect the City’s commitment to protecting public health, the effectiveness of these regulations will depend on the implementation of clear standards for inspection and sampling procedures, as well as improved transparency in reporting exceedance results. Enhancing these elements would ensure that regulatory oversight supports—not merely expands—the practical ability of building operators to prevent Legionella growth and reduce the risk of outbreaks across New York City.

  Comment added March 13, 2026 3:52pm

• EJD CWT NYC

  Subject: Public Comment on Proposed Changes to NYC Local Law 159 of 2025
  To the Relevant Agency / Rulemaking Committee:
  Below are a few more comments and concerns regarding the proposed changes under Local Law 159 of 2025. As an engineering and water treatment professional with over 40 years of experience, I share the common goal of all stakeholders—the public, building owners, operators, and water treatment professionals—in ensuring safe and well-maintained cooling tower systems. We all want effective, streamlined regulations that protect public health while recognizing the practical realities of facility management.
  Based on my professional experience, I urge the city to consider the additional points:

  First; my requests for specific templates and examples is inspired by experiences with the NYCDOHMH, OATH, and field inspectors. While the current legislation mandates adherence to industry standards like ASHRAE 188, inspectors utilize checklists derived from the NYC Model Cooling Tower Maintenance Program and Plan (CTMPP). Because this model— was originally adapted from NYC pool maintenance Plan —diverges from ASHRAE and HACCP principles, there is a lack of alignment between the law and enforcement. My objective is to synchronize our documentation, so it meets the inspector’s expectations in both form and sequence, ensuring a ‘right-first-time’ approach to compliance.
  Expanding the authorized user base for data entry would significantly alleviate the administrative burden of compliance. Allowing additional qualified staff to input information ensures that the city receives timely data

  Amend Section 8-02 to revise the definition of ANSI/ASHRAE 188 to remove direct reference to the sections and publication year, and instead reference “the latest edition” to allow future versions to be considered without requiring a new rulemaking each time.

  While this change may appear minor, its implications are significant. By tying local requirements to ASHRAE 188 or other evolving industry standards, we effectively alter legal responsibilities without the explicit authorization of the City Council or the NYC Department of Health and Mental Hygiene. Neither the Council nor the DOHMH should abdicate their regulatory power to outside organizations.

  Amend Section 8-02 to update the definitions of “cooling tower,” “cooling tower system;” “maintenance program and plan,” “qualified person,” “system shutdown” and “system startup;” and to add definitions of “cooling tower system components,” “commissioning,” “decommissioning,” “installation,” “operation” and “operation period” for clarification purposes.

  While many of these updates appear to be minor clarifications, the proposed definitions for ‘shutdown’ and ‘startup’ are overly broad and carry significant consequences. Under these terms, a standby pump or chiller inactive for more than five days would trigger mandatory full cleaning, disinfection, and Legionella testing of the cooling tower. This requirement has driven excessive energy consumption over the last decade. A trend that will only accelerate as heat pump systems with heat exchangers are cycled to meet these rigid standards. Ultimately, these operational costs and energy inefficiencies are passed directly to the tenants.
  It is important to distinguish between manual cleaning and chemical disinfection. While manual cleaning addresses the cooling tower structure itself, it has no impact on distant components such as pumps, chillers, or piping—which may be located hundreds of feet away. While systemic disinfection reaches these areas, requiring a manual tower scrub every time a remote component is cycled is technically ineffective and unnecessary.”
  The new requirement to notify the city within five days of starting up any system component—including the simple swapping of redundant pumps, chillers, or towers—is administratively excessive. When components are cycled or swapped after being offline for more than five days, this mandate creates a constant stream of low-value notifications. We suggest that routine equipment rotation should be exempt from this notification requirement to allow both operators and the Department to focus on high-risk system changes
  The proposed definition of ‘shutdown,’ which includes complete draining, poses a significant corrosion risk to older infrastructure. Introducing oxygen all winter in the absence of high levels of layup treatment mixed with water in cooling systems will necessitate specialized chemical passivators, plugging pipes and increased water treatment oversight to prevent pipe failure. Also, many systems cannot be completely drained. We request that the city provide a comprehensive risk analysis for this change. Currently most seasonal towers are only partially drained. Has this been linked to an outbreak?
  Also, please address how draining the system and the increased corrosion rates may promote Legionella growth by creating pitting corrosion, corrosion byproducts and ruff interior surfaces. This may possibly promote biofilm environments, thereby defeating the purpose of the mandate. Furthermore, the resulting chemical, maintenance and early equipment replacement costs will be passed directly to tenants.

  Amend Section 8-03 to require the preparer of the maintenance program and plan (MPP) for a cooling tower to annually certify the MPP, and to create a valve schedule as part of the MPP.

  We request further clarification and a specific template for the required certification. Creating a comprehensive valve schedule for cooling systems that utilize hundreds, or even thousands, of individual valves represents a significant administrative and engineering task. To ensure full compliance with City requirements and avoid unnecessary back-and-forth, we ask that the Department provide a sample certification or a clear example of the expected level of detail for such complex systems.

  Amend Sections 8-03, 8-04, 8-05 and 8-06 to reference the amended Section 8-07(a) for record production and retention requirements.

  Unannounced inspections frequently coincide with the absence of the primary responsible person or occur at facilities without full-time on-site staffing. In these instances, inspectors may arrive to find no one available to facilitate the review. To ensure the success of these inspections, we suggest a protocol for coordinating access at sites where staff are not permanently stationed.

  Amend Section 8-05 to require the inclusion of operating configurations that result in low flow or no flow to a cooling tower risk management assessment.
  Developing standardized protocols for some cooling systems is a formidable challenge, as many facilities operate under multiple configurations and highly variable load conditions. Please provide an example of how the city requires this change

  Amend Section 8-05 to require that fill water for the commissioning or startup of a cooling tower be obtained from a municipal water supply.

  We request a formal template or sample of an approved non-potable water source plan for makeup water. Despite three previous emails to [email protected] inquiring the specific procedures and requirements for an acceptable plan, we have yet to receive a response. Currently, in the absence of a clear approval process, systems are being forced to dump water unnecessarily to maintain technical compliance; a practice that contradicts the City’s broader sustainability goals.”
  Amend the corrective actions schedule set forth in Section 8-05 to reflect a single requirement that any results greater than or equal to 10,000 CFU/ml trigger a requirement for manual monitoring of the water treatment program.
  We request a specific example of the City’s preferred monitoring protocol for biocides that have no field test. Furthermore, since slug-dosing of halogens typically provides efficacy for only a few hours, a requirement for multiple manual daily checks is technically untenable. We need a monitoring framework that aligns with the chemical degradation rates of halogens. Some NYC procedures for legionella remediation only require a length of 1 hour. Please reconcile this discrepancy in protocols. Are bacteria more dangerous than legionella?
  Thank you for your time, consideration, and dedication to public health.
  Sincerely,
  EJD CWT NYC
  Certified Water Technologist
  Chemical engineer

  Comment added March 14, 2026 3:16pm

• Russell Baskin M.E., CWT, ASSE 12080 - President - Tower Water

  To:
  New York City Department of Health and Mental Hygiene
  Office of General Counsel
  Re: Proposed Amendments to Chapter 8 – Cooling Towers
  Reference Number: DOHMH 167 – March 16, 2026 Hearing

  Dear Commissioner and Members of the Department:
  My name is Russell M. Baskin, M.E., CWT, ASSE 12080 and I am the President of a commercial water treatment and Legionella compliance firm serving New York City building owners. I appreciate the opportunity to comment on the proposed amendments to Chapter 8 of Title 24 of the Rules of the City of New York.
  I support the Department’s public health mission and the intent of Local Law 159 to strengthen Legionella control. My comments focus on provisions that may benefit from clarification or adjustment to avoid unintended compliance risks while maintaining effective public health protection.

  1. Definition of “Operation”
  The proposed definition of “operation” treats a cooling tower system as operating anytime water is present, regardless of usage of the tower. This definition eliminates the distinction between active operation, standby conditions, lay-up, and residual water presence. This could include rainwater in a seasonal tower or a layup condition whereas a system is full of inhibitors and properly protected over the winter. There is a major concern with laying up open towers systems dry, when not in use. Oxygen in dry systems will cause major corrosion and peeling of old corrosion scale off piping this excessively deteriorates the system. Upon startup, this corrosion scale is eroded these pipes, due to the initial velocity of the water and air combination in the mains. These chips will and clogs the distribution deck, nozzles, and condenser tubes and strainers. This erosion can continue for a month or more, rendering the system inefficient and incurring emergency cleanings to removal of this debris. Owners of cooling towers should be able to wet layup these systems and drain just below roof level to protecting the interior piping. Upon start-up these systems, water can be drained refilled and disinfected, which will produce similar results, without the additional iron which is required for Legionella to proliferate. I respectfully request clarification on how this definition applies to seasonal water residual, lay-up systems, or redunant systems to avoid penalizing conditions that do not materially increase risk.

  2. Annual Maintenance Program and Plan Certification
  The proposed annual certification requirement raises questions regarding the scope and standard of responsibility for qualified persons or possibly associated qualified persons. Clarification is needed as to whether this certification represents a point in time document review or an ongoing assurance of operational compliance by the owner.

  3. “Improper Water Treatment” Enforcement
  The term “improper water treatment” is not objectively defined, yet carries significant penalties. I respectfully recommend that the Department define measurable criteria or cross reference specific control limits to ensure consistent and fair enforcement.

  4. Record Production Requirements
  The requirement that records be produced at the time of inspection, with failure deemed evidence that records do not exist, is punitive and does not reflect modern cloud based or third party recordkeeping practices. Consideration of a short, reasonable cure period would improve fairness without compromising oversight.

  5. Concerns with over burdening of “Qualified Persons”
  The new changes to chapter 8 title 24, produces additional responsibilities on “Qualified Persons”. This will limit the availability of such Qualified Persons. We in our professional opinion we believe qualified persons should be utilized for Water Management Plans, Risk Assessments, review of some reports, and excessive legionella readings as well as review of serious disinfections paperwork for legionella. We would recommend another designation as “Associate Qualified Person” or a “Junior Qualified Person” this person could have the ASSE 12080 “The ASSE 12080 certification focuses on water safety management, particularly in preventing legionella and other waterborne pathogens, and is essential for professionals involved in building water systems.” These people should be able to perform:
  • Inspections
  • Sample and resample for legionella
  • Review disinfection reports
  • Produce annual certification
  • Reassess and update WMP

  6. What constitutes a “Change” requiring re-certification mid-year?

  7. Can you explain the rational for HPC ≥10,000 CFU/mL now triggers:
  • Manual disinfectant residual monitoring 3x/day (it should be hourly during disinfection)

  8.New obligations of Notification will produce undue burden or expense if not followed properly – Buildings may need to pay suppliers or consultants to handle these notifications, otherwise fines will occur each year. Missed notification = automatic violation, even if health risk is controlled. These include:
  Notify the Department within 5 days of:
  • Startup
  • Shutdown
  • Operation period designation (is seasonal or all year sufficient?)
  • Legionella sample 3–14 days after startup

  Thank you for considering these comments. I appreciate the Department’s continued engagement with the regulated community and its commitment to public health.

  Respectfully submitted,
  Russell M. Baskin, ME, CWT
  President, Tower Water
  Somerset, New Jersey

  Comment added March 15, 2026 9:52pm

• Peter C

  “Local Law 159 of 2025 will go into effective May 7, 2026, and requires that Legionella sampling be conducted every month instead of every 90 days.”

  Please clarify every month

  1. 30 days?
  2. 31 days?
  3. Is sampling in compliance, if sample was collected on 6/1/26 and the next sample collected on 7/31/26?

  Comment added March 16, 2026 10:44am

• Anonymous

  The proposed rule includes a requirement to have weekly HPC samples analyzed by a laboratory accredited by the New York State Environmental Laboratory Approval Program (ELAP). Can you clarify whether the requirement to have samples analyzed by an ELAP accredited laboratory would also apply to dip slide testing? Given the specific temperature requirements for incubation, samples would need to be transported directly to a laboratory, which would create a burden for building owners.

  Comment added March 16, 2026 12:11pm

• Connor A.

  Our organization works closely with building owners and facility operators to support compliance with cooling tower regulations and water management practices intended to prevent the growth and transmission of Legionella bacteria. We support the Department’s continued efforts to protect public health and strengthen cooling tower oversight following the adoption of Local Law 159 of 2025.

  While we generally support the goals of the proposed amendments, we respectfully request clarification on several provisions that may present operational challenges or uncertainty for building owners, facility operators, and water treatment service providers responsible for implementing these requirements in practice.

  1. Monthly Legionella Sampling Requirements
  The proposed rule requires Legionella culture testing to occur at least once every calendar month, with no more than 31 days between sampling events while a cooling tower system is in operation. Clarification would be helpful regarding how the “calendar month” requirement should be applied when sampling occurs near the end of a month. If a sample is collected on the last day of a calendar month, would the next sample be required within the next calendar month or within 31 days of the prior sample?

  2. Manual Monitoring of Disinfectant Residuals
  Under the proposed revisions to Table 8-2, bacteriological indicator results greater than or equal to 10,000 CFU/ml would require manual monitoring of disinfectant residuals three times per day until target biocide residual levels are achieved. Because water treatment vendors are often not physically present at a facility multiple times per day, additional guidance would be helpful regarding who is expected to perform the required monitoring. Specifically, the Department may want to clarify whether such monitoring may be conducted by building engineering staff or other trained facility personnel and what documentation will be required to demonstrate compliance with this requirement. What about buildings that are not occupied? Also, Stakeholders would benefit from clarification regarding whether automated monitoring systems or remote sensors could satisfy the manual monitoring requirement.

  3. Record Production at the Time of Inspection
  The proposed amendments to Section 8-07(a) requires that records be provided to the Department at the time of inspection and indicate that failure to provide records may be considered “prima facie evidence” that the requirements were not satisfied. Because many records relating to water treatment services, testing results, and monitoring activities are maintained electronically or by third-party service providers, stakeholders would benefit from clarification regarding whether a reasonable period will be allowed to retrieve records not immediately available on-site.

  4. Coordination Between Startup Sampling and Monthly Testing Requirements
  The proposed amendments require Legionella culture sampling within 3 to 14 days following startup of a cooling tower system. Clarification would be helpful regarding how this requirement interacts with the monthly sampling requirement. For example, stakeholders would benefit from guidance on whether a startup sample may satisfy the monthly sampling requirement if the timing falls within the applicable testing interval.
  The Department’s continued efforts to strengthen cooling tower management standards and protect public health are appreciated. The questions outlined above are intended to support clear and practical implementation of the proposed rule. Additional clarification on these points would assist building owners, operators, and service providers in achieving full compliance while supporting the Department’s public health objectives.

  5. Weekly Dip Slide / Bacteriological Indicator Testing
  Under the proposed rules, can the Department confirm that dip slide microbial testing may be conducted onsite as opposed to mandatory submission of dip slides to an external certified laboratory for analysis?
  Additional clarification on these points would help building owners, operators, and service providers achieve full compliance while continuing to support the Department’s public health objectives.

  We appreciate your consideration of these comments and would welcome any additional guidance the Department may provide.

  Comment added March 16, 2026 1:15pm

• Homeyer Consulting Services, Inc.

  Thank you for the opportunity to actively participate in the mission of the NYCDOHMH to protect public health and to provide comment in the spirit of the amendments to Chapter 8.  We recognize this opportunity to present written comments as a serious and clear effort of the regulatory community to include the regulated community in our shared interest to protect the public health.

  By facilitating written input, the NYCDOHMH will now be able to gain from 40+ years of science and field experience of the regulated water user who is charged with providing real life, practical solutions for the reduction in the risk of Legionnaire’s Disease. The regulated community must take into account not only the regulatory rules and academic studies of Legionella but also the multi-dimensional realities of how these mechanical cooling systems operate.  Our company, along with several of the posted commentors, brings decades of experience in the practical, successful execution of Legionella control nationwide.  

  We hope that any changes are made with the public in mind as the cases of Legionellosis cases in NYC have not been significantly reduced since the inception of Local Law 77 based on data dating back to 2022 (NYC DOH Legionnaire’s Disease Annual Surveillance Report: https://www.nyc.gov/assets/doh/downloads/pdf/cd/legionnaires-surveillance-report.pdf  ). NYC DOH’s report identified 31 building evaluations (>2 cases associated with the same address to review all building’s water systems) compared to 2 community clusters, just between 2019-2022. When instituting such public health driven regulations, DOH should consider all aspects from a risk standpoint by including a greater focus on the incoming city water that allows cooling towers and building’s domestic water systems to continuously be inoculated by Legionella in the incoming city water.
   
  We respectfully submit our comments, alternative wording and solutions to the proposed amendments, striving to provide practical modifications that will keep with our shared mission of protecting of public health.

  Comment attachment
  health-code-chapter8-with-Homeyer-comments-March-16-2026.pdf

  Comment added March 16, 2026 2:50pm