Updated September 15, 2023

New and proposed Legionella regulations indicate that state and local officials in the US are heeding advice from the Centers for Disease Control and Prevention (CDC) to “consider changing building and public health codes to include Legionella water management programs.” 

Thankfully, the regulations are based on the same standard–ASHRAE 188–because consistency from state to state is key in preventing Legionnaires’ disease

Existing State Regulations for Legionella Control

Illinois Public Act 102-0004 (Article 90), adopted into law and effective April 27, 2021, requires hospitals and nursing care facilities to develop a policy for Legionella testing and make the policy and test results available to the state health department upon request.

Michigan Administrative Code R 325.45303, effective Feb 21, 2020, requires health facilities to implement a water management program (WMP) per ASHRAE 188 and the CDC toolkit. The WMP must include a risk assessment, control measures, and ongoing verification. Facilities with a secondary (supplemental) domestic water treatment must register as a public water supplier and comply with the Michigan Safe Water Drinking Act.

New York State regulations require a maintenance program and plan for all cooling towers, including Legionella testing. Hospitals and residential health care facilities must implement a Legionella “Sampling and Management Plan” also for potable (domestic) water systems.

New York City Local Law 77 and Chapter 8 of the Rules of the City of New York require cooling tower owners to implement a Maintenance Program and Plan (MPP) “that describes operational and administrative strategies and process control measures to be taken to prevent and control the growth of Legionella.” Legionella testing in cooling towers is required.

Virginia SB 410, effective July 2, 2021, requires schools to implement a water management program.

Proposed Legionella Regulations

New Jersey Senate Bill 1006 (March 10, 2022) replaced Bill 695. If adopted into law, Bill 1006 would require public water systems to maintain a free chlorine residual of at least 0.3 ppm (mg/L) throughout the system at all times and to provide customers written notice of disruptions that could result in increased levels of Legionella bacteria. Building operators would be required to implement a Legionella water management program (WMP) per ASHRAE Standard 188.

Pennsylvania Senate Bill 1125, introduced March 9, 2022, would require building operators to implement a water management program per ASHRAE 188.

Dead Bills

California Senate Bill 1144 — the Safe and Efficient Water Act — easily passed by the Legislature but was vetoed by Governor Newsom. It would have required the following for all buildings owned or leased by a public school or state agency:

  • A water quality and efficiency assessment including testing for Lead, Legionella and radon in potable water systems, water features, and cooling towers
  • A Legionella management plan, per ASHRAE Standard 188, in buildings with a cooling tower system, including routine sampling for Legionella and bacteria
  • Remediation of contaminant levels exceeding state safety standards
  • Notification to the public of contamination. If contaminant levels exceed state safety standards, a notice stating contaminants have been found in the building water systems must be posted in the lobby window near the primary entrance and clearly visible to the public. The notice must remain in place until the contamination is fully remediated.
  • Notification to the local health department within 24 hours of receiving a Legionella test result > 1,000 CFU/mL
  • A graywater reuse feasibility study
  • ASSE 12060 and 12080 certification for at least one person on the water management program (WMP) team and the applicable ASSE 12000 certification for each person providing water testing, remediation, and other WMP services.

Agencies would have until January 1, 2024 to meet requirements. Agencies operating more than one building would have to complete at least 25% of the buildings before 2024 and an additional 25% each subsequent year, completing all by January 1, 2027.

Maryland Senate Bill 302 – Legionnaires’ Disease Prevention Act (Jan 20, 2022) – and the identical bill in the house (HB 248) would have required owners or operators of public buildings to implement a Legionella water management program that is consistent with ASHRAE Standard 188 and includes validation testing, but it was vetoed.

North Carolina House Bill DRH30401-MGa-137A, the “Legionnaires’ Disease Prevention Act,” which would have required building owners and operators to implement a water management plan (WMP) per ASHRAE Standard 188 and to perform validation testing, was replaced with funding for a Legionella Prevention Study.


If you have access to LAMPS, refer to the Training Notes for details about each regulation.

Although a water management plan in LAMPS is populated with content specific to applicable state regulations, you should still check with your state to confirm its requirements and ensure that your WMP satisfies those requirements.

If you are not required by regulations to implement a Legionella water management plan, do it anyway per ASHRAE standards 188 and 514. In addition to protecting health and life, a good water management program can make your building truly healthy and smart, promoting wellness and saving energy.

David Swiderski is the Senior Technical Strategist, and Matt Freije the CEO, at HC Info.

We will update this article as we receive new information. Do you know of other proposed Legionella regulations? If so, please comment below.

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