Legionella Management in Building Water Systems

Developments in State Policy


New York City


Citation: N.Y.C. Local Law No. 77 (codified at N.Y.C. Admin. Code 28-317.1—28-317.7 and 17-194.1); 24 Rules of the City of New York (RCNY) 8-01—8-09


Local Law: http://www1.nyc.gov/assets/buildings/pdf/ll77of2015.pdf

Administrative Code: Here 

Rules: Here


Summary: New York City law and implementing rules adopted by the Department of Health and Mental Hygiene (DOHMH) require all cooling tower owners to create a maintenance plan and program that complies with certain elements of ASHRAE Standard 188 and with additional requirements specified in the law and rules for inspection, cleaning, disinfection, testing and corrective actions. The law also requires registration of all cooling towers with the city. The department must submit to the mayor and city council an annual report to include sampling and corrective action undertaken by cooling tower owners.

Key Provisions:

Requirement for a Legionella Maintenance Plan and Program

The owner of a building with a cooling tower is required to develop and implement a maintenance plan and program that complies with Sections 5, 6 and 7.2 of ASHRAE 188 and with manufacturer instructions, and the system must be maintained in accordance with the plan. The plan must be developed by a qualified person and must be maintained by a qualified or responsible person, as those terms are defined in the regulations. 24 RCNY 8-03, 8-04; N.Y.C. Admin. Code 17-194.1. 

The plan must include information specified in the rules on the following topics: (1) management and maintenance team; (2) cooling tower system; (3) risk management assessment addressing a variety of system risk factors for Legionella growth and (4) cooling tower operation. 24 RCNY 8-03. The plan must specify a cleaning protocol and worker protective measures, as well as water quality monitoring parameters and frequency as specified in the rules. 24 RCNY 8-04(c). The plan also must include the procedures and protocols for corrective actions, as specified in the rules (see below). 24 RCNY 8-05(f)(5).

Other Specific Requirements

System Monitoring. Owners must designate a “responsible” person as defined in the rules to monitor each cooling tower according to criteria in the rules. 24 RCNY 8-04(a).

Inspections. A qualified person (as described in the law and rules) must be retained to conduct compliance inspections and record the findings at least every three months while a cooling tower is in operation. 24 RCNY 8-04(b); NYC Admin. Code 17-194.1(e),(f).

Cleaning. Cleaning must take place when needed, but at least twice per year. 24 RCNY 8-04(d).

Aerosol and Mist Control. The cooling tower must be operated to minimize the release of aerosols and mist, including through the installation of drift eliminators, and the rules specify requirements for drift loss. 24 RCNY 8-04(e).

Water Treatment. The rules include a variety of treatment requirements, including daily automatic treatment, use of a recirculating system and use of chemicals and biocides. 24 RCNY 8-05.

Water Quality Monitoring. The rules provide for routine Legionella culture testing at least every three months and emergency culture testing in certain situations, with samples analyzed by a New York State- or CDC-approved lab or other lab approved by NYC DOHMH. The rules also require weekly microbial monitoring. Monitoring for temperature, pH, conductivity and biocides must either be automated or performed manually three times per week. 24 RCNY 8-05(f).

Corrective Action. The rules set forth specific requirements for corrective actions in response to Legionella culture and bacteriological indicator results. Corrective actions for Legionella culture results are tiered according to result levels, which parallel the Legionella data interpretation guidelines set forth in Table 3.1 of the American Industrial Hygiene Association’s Guidelines, Recognition, Evaluation, and Control of Legionella in Building Water Systems. 24 RCNY 8-05(f)(5).

Commissioning and Decommissioning. The rules establish requirements for cleaning, sampling and notification when a cooling tower is shut down or restarted. 24 RCNY 8-06.

Agency Oversight

Registration and Certification. The law requires owners of existing and new cooling towers to register their towers by providing information about each tower to the city’s Department of Buildings. Owners must notify the Department of Buildings within 30 days after removing or discontinuing a tower. NYC Admin. Code 28-317.3, 17-194.1(b); 24 RCNY 8-06. Cooling tower owners must also file that department an annual certification of the activities carried out in in accordance with the management plan, including any deviations from compliance and corrective actions. NYC Admin. Code 28-317.5; RCNY 8-07(b). The department may charge a fee for these filings. NYC Admin. Code 28-317.6.

Recordkeeping. Owners are required to keep for at least three years records of activities governed by the rules. NYC Admin. Code 17-194.1(h); 24 RCNY 8-07(a).

Reporting. Owners must report to NYC DOHMH within 24 hours an exceedance of a Legionella culture sample as specified in the rules. 24 RCNY 8-05(f)(3).

Inspections and Sampling. The law authorizes city officials to inspect cooling towers and review records to determine compliance with the law and regulations. NYC Admin. Code 17-194.1(i).

Waivers. The NYC DOHMH may grant a modification of any specific requirement under the rules in cases of “practical difficulties or unusual hardships.” 24 RCNY 8-08.

Enforcement. The rules establish penalties that “shall be imposed for sustained initial and repeat violations” of the rules. 24 RCNY 8-09.

The NYC DOHMH undertakes annual inspections of cooling tower systems, maintenance plans and programs and operational records. The department has created a chart listing the minimum fines for deficiencies observed during city inspections, as provided in the rules. The city also offers compliance assistance training to building owners and has developed a Cooling Tower Self Assessment Tool. See NYC Health, Cooling Tower Registration and Maintenance, https://www1.nyc.gov/site/doh/business/permits-and-licenses/cooling-towers.page.


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