Protection Against Legionella: Cooling Tower Requirements

A cooling tower is part of a recirculated water system incorporated into a building's cooling, industrial, refrigeration or energy production system.  All owners of cooling towers in New York State are required to register their towers in the New York State Cooling Tower Registry, prepare and implement a Maintenance Program and Plan, test their towers for Legionella, clean and disinfect them, and notify their local health department and the public when they identify elevated levels of Legionella in their cooling tower water. Cooling towers are tested for Legionella to assess the effectiveness of routine disinfection and maintenance.

Resources for cooling tower owners, operators, water treatment consultants and inspectors are provided below.   The regulations are listed in New York State Sanitary Code Part 4.


Cooling Tower Registry

All cooling towers owners in New York State must register their towers and maintain their records on the New York State Cooling Tower Registry.  Registries must be updated at least every 90 days while the tower is operational.  Download the user guide for step-by-step instructions on using the Cooling Tower Registry.

If you need to change your cooling tower registry account to another ID user, or if the building has been sold or leased to another party that is legally responsible for the cooling tower maintenance, use the Cooling Tower Registry Change of Account Ownership Request form 

Notification of Exceedance

Cooling tower owners must notify the Rockland County Department of Health within 24 hours of receipt of a Legionella culture sample result that exceeds 1,000 colony forming units per milliliter (CFU/mL).  Owners must also notify the public of test results in the manner determined by the Rockland County Department of Health or the New York State Department of Health.

Maintenance Program and Plan

Prior to the initial start-up of a newly installed cooling tower, the owner must develop a Maintenance program and plan.  Each active cooling tower must have an updated Maintenance program and plan, which must be developed in accordance with ASHRAE Standard 188-2018 Legionellosis: Risk Management for Building Water Systems.  A Maintenance Program and Plan template is available to download.

Culture Analysis

Cooling towers must be sampled for Legionella at least every 90 days, and all Legionella culture analyses must be performed by a laboratory certified by the New York State Environmental Laboratory Approval Program (ELAP). 

Bacteriological culture sample collection must be performed at least every 30 days using dip slides or heterotrophic plate counts. This test can performed by cooling tower service providers analyzed in house.




Any person who disinfects a cooling tower must be a certified commercial pesticide applicator or pesticide technician who is qualified to apply biocide in a cooling tower.  Only biocide products registered by the New York State Department of Environmental Conservation for use in cooling towers or pesticidal devices produced in a USEPA registered establishment may be used in disinfection.

Variances and Waivers

An owner may submit a written application to the New York State Department of Health for a variance for a period not exceeding 90 days from any provision.  It must include an explanation of why the variance will not present a danger to public health.

The New York State Department of Health may issue a waiver for any provision of the regulation if staff are satisfied that the waiver would not present a danger to public health.  Waivers may also be revoked upon determination that the waiver may present a danger to public health.  To apply for a waiver, please email

Inspections and Certification

All cooling towers must be inspected prior to seasonal start-up and every 90 days while in use.  Cooling towers also need to be inspected following maintenance.

All cooling towers must obtain a certification by November 1 of each year.  The certification should attest that the cooling tower has a maintenance program and plan, and that all activities within that plan or required by the regulation were implemented.  An annual certification documentation template is available to download.

For additional information, please contact:

NYSDOH, Bureau of Water Supply Protection at 518-402-7650 or

Rockland County Department of Health at 845-364-3682 or

Related Links: