New York City vs New York State Legionella Laws – The Definitive Guide

Posted by Greg Frazier on Tue, Sep 27, 2016 @ 09:15 PM


Since the Legionella Outbreak of 2015 in the South Bronx, there has been a lot of confusion over the following topics: What is Legionella and what needs to be done in New York City and New York State to be in compliance with the new cooling tower laws.  The City and State laws were recently passed with the intention of preventing the spread of Legionella bacteria through cooling towers. As the agents from the various local health departments throughout New York begin to enforce compliance throughout the state, building owners look to their environmental consultants and water treatment companies for answers. The problem is that the New York City laws only pertain to properties that are located in the 5 Boroughs of NYC and they are slightly different than the laws that pertain to rest of the State of New York. Hopefully, this post will clear up a lot of the confusion. 

New York City’s Legionella Laws are governed by Local Law 77 of 2015 and Title 24 Chapter 8 of the Rules of The City of New York and New York State’s Emergency Regulations have been ratified in the newly adopted New York Codes, Rules and Regulations, Title 10 – Part 4: Protection Against Legionella (Part 4 to Title 10 NYCRR). There are many similarities between the City and State laws. In fact, they overlap in many areas, so complying with one often covers you for the other; however, there are a few differences that you will want to keep in mind. Let go through the important ones:

Registering Your Cooling Tower

Both the City and State require you to register your cooling towers on their individual systems. This can be done online. For the State, go to and for the City, go to This is very important! If your cooling tower is located in one of the 5 Boroughs of NYC, you MUST register it on BOTH the CITY and the STATE websites. Also, if you have more than one cooling tower, you must register EACH ONE individually.

Labeling Your Cooling Tower

Even though New York City cooling towers must be obtain registration numbers from both the City and State websites, only New York City cooling towers are required to have the City Cooling Tower Registration Number permanently affixed to the outside of the tower in a visible location. NY State does not have this requirement.

Having a Maintenance Program and Plan (MPP)

Sometimes also referred to as a Water Management Plan, having an updated Cooling Tower Maintenance Program and Plan (MPP) is required by BOTH the NY City and State laws. Compliance for both requires you to have one plan for each cooling tower on your property by September 1st, 2016.  Your MPP must include your schedule for routine bacteriological culture sampling, a system for cooling tower water treatment, a plan for routine Legionella culture sampling and analysis, a plan for immediate Legionella culture sampling and analysis under specific conditions and the contact information for all of the responsible people tasked with implementing the plan. The plan must be kept on-site and must be produced whenever an authorized agent of the City or State requests it.

Testing Your Cooling Tower

The City and State have very different requirements for testing your cooling tower. There are three major areas of testing:

  1. General Bacteriological Testing – Pertains to BOTH the City and State. This type of testing is easily done on site with a simple dipslide culture test. Both the City and the State say that you must conduct bacteriological culture sampling and analysis to assess microbiological activity in the cooling tower. This can essentially be performed using a simple dipslide test. Dipslides are very easy to use. Dip the slide into the tower basin, wait 24 hours, count the number of dots that appear on the slide and record your findings. 

The big difference between the City and the State’s biological testing requirements is in the intervals. The State wants your dipslide test results recorded every 30 days, but the City wants it done once per week while the tower is in operation. Obviously if you are adhering to the City law, you are already fulfilling the State requirement as well. 

Both the City and the State want you to keep a record of your test results. However, the State law also requires the owner of the cooling to report the date and results of their most recent bacteriological test, every 90 days while a cooling tower is in use, using the statewide online electronic system. 

  1. Legionella Specific Sampling & Analysis – The rules for Legionella testing pertain to BOTH the City and State. The new State regulation requires sampling within two weeks of seasonal start-up and thereafter at intervals not to exceed 90 days. In addition, the new regulation requires that year-round use towers be sampled at intervals not to exceed 90 days and within two weeks after start-up following maintenance.

The City and the State also require immediate Legionella sampling to be conducted if the following happens: 

  1. power failure of sufficient duration to allow for the growth of bacteria;
  2. loss of biocide treatment of sufficient duration to allow for the growth of bacteria;
  3. failure of conductivity control, or any other control methods, to maintain proper cycles of concentration;
  4. a determination by the department or local health department that one or more cases of legionellosis is or may be associated with the cooling tower, based upon epidemiologic data or laboratory testing; and/or
  5. any other conditions specified by the department or local health department.

The NY State law requires that samples be sent to an ELAP Certified Lab for analysis. The City does not require you to use an ELAP Certified Lab, but it does require an ELITE Certified Lab; so to be compliant, make sure your samples are analyzed by the right Lab. Most ELAP Certified Labs are also ELITE Certified.

Like the dipslide tests, both the City and the State want you to keep a record of your Legionella sampling and test results. However, the State law also requires the owner of the cooling to submit the date of last Legionella culture sample collection, the analysis result(s), and the date of any required remedial action, every 90 days while a cooling tower is in use, using their statewide online electronic system. 

  1. General Water Quality Testing – Pertains ONLY to New York City and can easily be performed on-site with a simple test kit. Parameters to be tested must include pH, temperature, conductivity and biocidal indicators (biocides), must be measured and recorded as specified in your Management Program and Plan.

Water quality tests must be performed at least three times each week, provided that no more than two days pass without testing while the cooling tower system is in operation. All test results must be recorded for each tower system and kept on-site to be made available to department officials upon request.

Weekly Cooling Tower Inspections

New York City legislation requires that an owner must designate a responsible person to monitor each cooling tower system at least weekly while such system is in use. This person must use a written or electronic checklist to record all visual observations of the cooling tower system and associated equipment. This part of the City law requires that the designated person physically observe all wetted surfaces visible during cooling tower operation (without having to shut down the system), including tower basins and drift eliminators. They must examine the tower for the presence of organic material, biofilm, algae, scale, sediment and silt/dust deposits, organics (oil and grease), and other visible contaminants and must denote them on the checklist.

The responsible person must also observe and note the condition of chemical dosing and control equipment and of the tower bleed system, and determine if there is sufficient storage and delivery of treatment chemicals. Any system anomalies, issues or problems must be recorded on the checklist and reported to the management and maintenance team for immediate corrective action.

This weekly inspection requirement is only found in the New York CITY legislation, not in the State.

Performing 90-Day Inspections

According to BOTH the City and State laws, an owner must retain a “qualified person” to conduct a compliance inspection at least once every ninety (90) days while a cooling tower system is in operation. The qualified person must complete and the owner must maintain a written or electronic checklist containing observations and findings with respect to any of the following:

  1. Presence of organic material, biofilm, algae, and other visible contaminants.
  2. General condition of the tower, the basin, packing material and drift eliminator.
  3. Quality of water makeup connections and control.
  4. Proper functioning of the conductivity control.
  5. Proper functioning of all dosing equipment (pumps, strain gauges).
  6. Review of routine maintenance records to ensure proper implementation of required activities and corrective actions as needed.

Obtaining an Annual Certification

To satisfy the requirements of both the New York City and New York State legionella laws, owners must obtain a written certification from a “qualified person” once per year (starting on November 1st, 2016 and then by November 1st of each year thereafter), stating that the cooling tower system has an active Maintenance Program and Plan (MPP) in place and that all activities stated within that plan or required by law were properly implemented, including but not limited to:

  1. That all bacteriological culture samples and analysis were performed properly and timely;
  2. That all Legionella culture samples and analysis were performed properly and timely;
  3. That any disinfection was performed properly and as per the law;
  4. That all inspections were performed as per the law;
  5. That all inspection findings, deficiencies, and corrective actions, and all certifications, were reported to the owner, who shall retain such information, in accordance with the law.

Clean and Disinfect Cooling Towers at LEAST Twice per Year

According to the City law, the cooling tower system must be cleaned whenever routine monitoring indicates a need for cleaning, but no less than twice a year, in accordance with your Maintenance Program and Plan (MPP). Cleaning protocol indicated by the manufacturer’s instructions or industry standards, and worker protective measures, as required by applicable law must be specified in the MMP. Water contact areas such as the basin, sump, fill, spray nozzles and fittings, drift eliminators and air intake louvres must be properly accessed or removed to facilitate cleaning.

The State does not have this requirement, however, both the City and State require that the tower system be disinfected whenever a cooling tower that has been shut down or idle for more than five days.

Using a “Qualified Person” for Required Tasks

Throughout the City and State laws the term “qualified person” is used quite a bit. You must use a “qualified person” to do conduct your compliance inspection or disinfect your tower, etc. It can get a little confusing.

This is important because there are different requirements for different tasks that must be performed. In other words, the employee on your team or the vendor that you hired to clean your disinfect your cooling tower may not necessarily be qualified to perform your mandatory quarterly inspections. 

Here are the main areas where you need to pay attention:

  1. 90-Day Compliance Inspections and Yearly Certifications

New York City and New York State require that 90-Day Compliance Inspections and Annual Certification of maintenance and operation be performed by a New York State licensed and registered professional engineer; a certified industrial hygienist; a certified water technologist with training and experience developing maintenance plans and performing inspections in accordance with current standard industry protocols including, but not limited to ANSI/ASHRAE 188-2015; or an environmental consultant with at least two years of operational experience in water management planning and operation.

  1. Maintenance Program and Plan Development

New York State merely says that you need to obtain one and have it on-site; it doesn’t specify where to get it, so technically it can be written by someone with experience on your staff. New York City, however, is very specific about who can develop and sign off on a Cooling Tower Maintenance Program and Plan. It is a “Qualified Person” that meets the same requirements for issuing a 90-Day Compliance Inspection or Yearly Certification. (See above)

  1. Ongoing Water Treatment

In order to maintain a cooling tower that complies with the City and State laws, you must have ongoing water treatment on your tower that is administered automatically while the tower is in operation. Your water treatment program MUST utilize a biocide. New York City and State both require that any use of biocides (i.e. disinfecting chemicals) be done by a commercial pesticide applicator, a pesticide technician certified in accordance with the requirements of New York State’s Pesticides Regulations (Environmental Conservation Law Article 33 and Title 6 of the New York Codes, Rules and Regulations [NYCRR], Part 325), or a pesticide apprentice under the supervision of a certified applicator. The New York State Department of Environmental Conservation (NYSDEC) provides a list of registered pesticide businesses in Category 7G (“Cooling Towers”) who are qualified to perform the disinfection process. Unless someone on your staff meets this requirement, you may not treat or disinfect your own cooling tower with a biocide.

  1. Cooling Tower Cleaning and Disinfection

The only acceptable method of disinfecting a cooling tower is by administering biocide at proper doses and, therefore, must be handled by a commercial pesticide applicator in accordance with New York law as above. Cleaning activities that do not use any of the chemicals described above, such as basic scrubbing or power washing, do not need to be performed by a person qualified to apply pesticides.

Performing an Emergency Legionella Test

Both the City and State Laws require cooling tower owners to perform an immediate Legionella culture test and analysis when one of the following issues occurs:

  • When there is instance of power failure of sufficient duration to allow for the growth of bacteria.
  • When there is instance of loss of biocide treatment of sufficient duration to allow for the growth of bacteria.
  • When there is instance of failure of conductivity control, or any other control methods, to maintain proper cycles of concentration.
  • When there is a determination by the department or local health department that one or more cases of legionellosis is or may be associated with the cooling tower, based upon epidemiologic data or laboratory testing.

So you may be thinking that the phrase “of sufficient duration to allow for the growth of bacteria” is more than a bit subjective; that’s because it is. However, there are some guidelines that should be considered.  Legionella will grow in water that is approximately 70 to 113 °F with the ideal growth range being 90 to 108 °F. If your cooling tower loses flow and/or biocide for more than 24 hours and the water temperature is within these ranges, there is a significant chance that you are starting to breed Legionella in your tower.

That said, we are of the opinion that, since there is no specific parameter for testing, testing for it is not nearly as important as actively disinfecting. Legionella test results can take up to 10 days to get back from the lab; in that time your cooling tower may be teeming with Legionella. After a 24 hour loss of power or biocide, the responsible solution is to immediately increase biocide feed to disinfect the tower. 

Notifying the Department of Health and Public When There is a HIGH Legionella Count

In the event that you test your cooling tower for Legionella and the results come back showing that there are more than 1,000 colony forming units per milliliter of water (CFU/mL), both the City and State require that you immediately clean and disinfect your tower and contact your local Department of Health within 24 hours of receipt if that information. The New York State law goes a bit further though.

The State law says that, in the case where the culture sample exceeds 1,000 CFU/mL, the owner must also notify the public. The specific section of the law can be found in NYCRR Title 10 Part 4: Protection Against Legionella:

  • 4-1.6 Notification.

(a) The owner of a cooling tower shall notify the local health department within 24 hours of receipt of a Legionella culture sample result that exceeds 1,000 colony forming units per milliliter (CFU/mL). The local health department shall notify the state department of health with 24 hours of receipt of such a report. 

(b) The owner shall notify the public of such test results in a manner determined by the local health department or, in the event that the department elects to determine the manner of public notification, by the department. 

So what does this mean exactly? The law states that the public MUST be notified, but it doesn’t express the exact method of notification, except to say that it must be in a manner determined by the local health department, which technically means that the department of health could potentially require your facility to take out a full page public ad in the local newspaper.  

However, in similar cases where there is a likely health related issue tied to a location, the local health department (or sometimes the building owner) will issue a letter to all building occupants informing them that there is has been a potential problem reported to the department; in this case - that a medical professional or hospital has reported an instance of Legionella at the address. The letter sent may describe the potentially elevated risk to susceptible people (such as the very young, the elderly or those that may be immuno-compromised) and may also inform them of the steps that the owner is taking in by direction of the health department, and the precautionary measures that the occupants may take to further minimize their risk.

Regardless of the mode of notification, it goes without saying that any place of business or public institutional entity (like a school, hospital or housing facility) could be deeply impacted by a public admission of this nature. This one provision of the New York State Legionella law is perhaps its most critical.   

Record Keeping

Both the City and State require that all records related to your cooling towers’ maintenance and compliance must be kept for a minimum of three years, including the City’s weekly water quality and biological testing results, the State’s monthly biological testing results, all Cooling Tower Cleaning & Disinfection Certificates, all 90-Day Compliance Inspection Reports, all Legionella Sampling and Analysis Reports and all Annual Certification Reports.

These records, along with your Maintenance Program and Plan (MPP) must be made available to the NYSDOH and the local health department; furthermore, the STATE requires that all inspection reports (90-Day and Annual Certification) be uploaded to their electronic system.  So every 90 Days cooling tower owners must log into the online State system and UPLOAD their reports.

Additional New York STATE Requirements for Health Care Facilities

Because of the increased vulnerability of hospital and nursing home populations due to their advanced ages and/or potentially compromised immune systems, the new State regulations include additional requirements for hospitals and residential health care facilities that have cooling towers.

By Sept. 1, 2016, these facilities must perform or update their existing environmental assessment, using forms mandated by the NYSDOH, in order to evaluate all of the building’s water systems, including the potable water systems, and identify sampling locations. This plan must be updated annually. Environmental assessments are standardized through use of the NY State Environmental Assessment Forms.

Additionally, all general hospitals and residential health care facilities must adopt and implement a sampling and management plan for potable water systems by Dec. 1, 2016, which includes routine Legionella culture sampling and analysis and immediate Legionella sampling and analysis under specific conditions, including where the NYSDOH determines that one or more cases of legionellosis is, or may be, associated with the facility.

These facilities must conduct their Legionella culture sampling and analysis at intervals no greater than 90 days for the first year and annually thereafter. In cases where the potable water systems serve stem cell or organ transplant patients, they must continue to be sampled and analyzed at intervals not to exceed 90 days even after the first year.

The Legal Stuff

Please be aware: Clarity Water Technologies is not responsible for the accuracy or implementation of information contained within this post or to the sites linked to this post. This blog is for information purposes only. By using this information in ANY way, you are hereby agreeing to fully defend, indemnify and hold harmless Clarity Water Technologies from and against any and all losses, claims, suits or other legal liability and legal expenses of any nature imposed upon or brought against them by reason of any act or omission of Clarity Water Technologies or its agents or employees that may arise in use of this document. 

As always, thank you for reading!

PS - If you would like to see the differences between the NY CITY and STATE Legionella Laws at-a-glance, please download our free side-by-side comparison chart:

Download NY City and State Cooling Tower Laws Side by Side Comparison Chart


Commercial and Industrial Water Treatment ServicesClarity Water Technologies is known throughout the east coast as an innovative industrial/commercial water treatment company and the innovators of 360 Degree Legionella Management Service. To put it simply: As New York City's Top Environmental Consultants, we make commercial HVAC and industrial process machinery last longer and run more efficiently, with less fuel and less downtime, by chemically treating the water that runs through it. Typical systems that we treat include steam boilers, chillers and cooling towers; however, we also offer advanced wastewater, glycol services, odor control and fuel treatment services. We are one of Northeast’s most trusted Legionella remediation companies and are widely accepted as one of the best consulting firms to establish best practices for the implementation of ASHRAE Standard 188 - Legionellosis: Risk Management for Building Water Systems.

As environmental consultants specializing in water treatment, we know that chemistry is only one part of what makes a cooling tower system operate at peak performance. The other part of the equation is proper physical cleaning, disinfection and maintenance. Today, Clarity offers one of the most reliable and effective cooling tower disinfection services available throughout NY, NJ, CT, DE, MD and PA. Clarity is a NADCA Certified HVAC Cleaning Service Company. Our team also offers on-line cleanings, chlorine dioxide disinfection, Legionella remediation and installation of the EcoSAFE Solid Feed System—one of the most advanced water treatment systems for Cooling Towers in the world! Please contact us today for a free estimate on your next project.

Greg_Frazier_Industrial_Water_Treatment_ProviderNew York Water Treatment Professional and Environmental Consultant, Greg Frazier has a vast knowledge of Industrial Water Treatment and is currently the Managing Partner of Clarity Water Technologies, one of the top Water Treatment Companies in the United States. Mr. Frazier has over 19 years of Industrial Water Treatment experience and holds a degree in Chemical Engineering from the University of Tennessee. Clarity Water Technologies specializes in comprehensive water treatment services. Clarity's service goes far beyond administering Cooling Tower Water Treatment chemicals - it also includes Cooling Tower Maintenance and HVAC Cleaning Services.

Tags: Cooling Tower Water Treatment, Water Treatment Companies, Chapter 8 Title 24 RCNY, NYCRR Title 10 Part 4, Legionella Testing, Legionella Bacteria, New York City Legionella Laws, What is Legionella, Legionella Laws, New York State Legionella Laws