Legionnaires’ disease is the leading cause of reported waterborne disease outbreaks, hospitalizations and deaths in the US between 2015 and 2020. It is caused by Legionella bacteria, a pathogen that can quickly grow inside water pipes, spas and cooling towers where water circulates between 77 and 113°F. While large buildings are at higher risk of Legionella growth because of the size and complexity of their piping system, all buildings should manage the risk as outbreaks have been reported in smaller building typologies such as private residences. The management strategies, however, should be proportional to the risk; small buildings may not need to hire an expert to develop a plan, and instead use simple measures to assess and update risk on a regular basis. With these considerations in mind, here is a how-to guide to implement a water management plan in smaller properties or subsets of larger buildings that meets the requirements of the WELL feature W03.2: Implement a Legionella Management Plan.

1. Scope the plan preparation

• Utilize a Legionella risk assessment tool developed by an appropriate health agency, such as the U.S. CDC’s Legionella worksheet, to determine if your building needs to implement a Legionella water management plan. 

  • If a full-fledged, building-wide water management plan is suggested, it is advisable to hire a specialist to develop the plan. If you manage a space within a large building, it is possible that your landlord already has a compliant plan in place. If this is the case, you can use the building’s water management plan to support your WELL submission. 

  • Implementing a full-fledged water management plan that requires hiring a specialist may not be necessary if the assessment tool states so. 

  • A full-fledged water management plan may also not be needed if you:

    • Manage a tenant space that is a relatively small section of a large building operated by a landlord (such an office space, a showroom or a retail space), and

    • Your space doesn’t include a large number of showers or hot water faucets, and 

    • Your space doesn’t include any specialty water devices such as a cooling tower, misters, spas or hot water pools.

  • If you determine that a full-fledged water management plan is not needed, WELL feature W03.2 Implement Legionella Management Plan still requires that a basic water management plan be implemented. This requirement is in alignment with the US CDC’s broader recommendations to maintain water devices. 

    • For spaces with very simple plumbing set-ups and minimal hot water fixtures, filling the requirements for this feature should take an on-site visit and approximately 1-2 hours of work.

    • If you manage a tenant space within a building, work with your landlord and/or building manager. In some cases, they may be able to provide enough information about their building-wide water management plan to properly document compliance with this feature. If they are uncooperative or do not have enough information, utilize your basic water management plan to document your attempts to approach them and disclose any information provided. This information may help satisfy some of the WELL feature requirements.

  • The steps below provide suggestions on what to consider when developing a water management plan that meets the WELL feature requirements. As mentioned, a specialist may not be needed to develop this water management plan. The plan should address what is most applicable to the project; it is not required to include every detail described.

2. Determine roles

Address requirement (b)(1): Determination of roles for Legionella management in the building, distinguishing those under project control from those that may be the responsibility of building management or other parties.

• The water management plan should document a list of the relevant roles for people in charge of assessing and managing Legionella risk in your location. This list should include:

  • The person who assessed the project’s risk factors associated with Legionella.

  • The plan preparer (whether developing a basic or full-fledged plan)

  • The plan executer or maintainer, usually an office or building staff

  • If the space is part of a larger building, the role of the personnel managing the building operations

3. Make an asset inventory

Address the first part of requirement (b)(2): Water system inventory within the project boundary.

• Count and document the location of the hot water faucets and showerheads in your space. Also include any cooling towers, spas, misters, fountains and other devices where lukewarm or hot water may recirculate (note that these devices may need to be assessed for Legionella risk by a specialist). An unheated pool without sprayers or misters does not need to be considered. Include the inventory and their locations within the water management plan.

4. Make a simple diagram of the hot water piping

Address the second part of requirement (b)(2): Process flow diagrams of systems within the project boundary

• The water management plan should include a diagram that shows how the hot water pipes are connected. An example of a common case is shown below:

• If you are not familiar with the plumbing and cannot find the plumbing diagrams for your space or building, inquire with the building manager or someone knowledgeable of the building. Many problems in water quality begin by not knowing how the plumbing is set up.

• If none of the above are possible, your basic water management plan should include  photos documenting the piping under the sinks with accompanying descriptions of the corresponding rooms.

5. Assess Risk

Address requirement (b)(3): Hazard analysis of water assets within the project boundary. If the project does not operate the building hot water supply system (e.g., boilers, heaters, pumps or hot water risers), then an explanation of the building-wide Legionella management policies (if any) and how they influence risk is included.

• The water management plan should document the following:

  • The outcome from the Legionella risk assessment tool (e.g., CDC toolkit, see ‘scope the plan preparation’ section) stating that, based on the tool, a full-fledged legionella management plan is deemed unnecessary.

  • If the project area is within a larger building, information about the building-wide water management plan (e.g., whether or not it exists, explanation as to whether it covers the water fixtures in your tenant space, the building POC, etc.).

    • Ask the building management whether a building-wide water management plan has been implemented or not. A managed building poses less risk than a building that does not manage its water quality. Describe in your plan your actions to engage landlords and/or building managers and whether they are cooperative in your risk assessment process.

    • If a building-wide water management plan exists, determine whether it addresses the water fixtures within your space (which may be the case if you have not added or modified internal plumbing as part of your construction scope). If this is the case, you can use the base building’s water management plan in lieu of creating a new one.

  • Disclosure of any “dead legs” in your hot water line. Dead legs are pieces of piping through which water cannot flow, usually installed for future connections. They are a known risk factor because they provide a place for water to stagnate and become a haven for microbial growth. To assess your space for dead legs, look for them under the faucets in bathrooms and kitchens that provide hot or warm water.

6. Establish protocols for monitoring

Address requirement (b)(4): A list of monitoring actions for relevant variables (e.g., temperature or residual chlorine), performance limits associated with these variables, and corrective actions when variables exceed such limits.

• The water management plan should include a commitment to record the hot water temperature and time it takes water to get hot on a periodic basis (quarterly or every six months). This is a simple, yet very effective way to assess the risk for Legionella in hot water. Specify one tap for every five faucets or showerheads, using the diagram from (b)(2) to identify these points. With a thermometer and a timer at hand, perform the following:

  • Wait 10 minutes since its last use.

  • Set the tap at its hottest setting, start the water flow and the timer.

  • Keep measuring the temperature until it begins to stabilize (i.e. stops getting hotter). Record the stable hot temperature as well as how long it took to stabilize.

  • If the water takes more than a minute to reach its hottest setting, check with a plumber and/or the building manager about the cause of the delay. 

  • Ideally, the hot water temperature in a building should run at 120-130°F. For scalding protection, showers may deliver hot water at 110°F and hand washing taps at 120°F. Write down the hottest water temperature delivered at the faucet. 

    • If your hot water is mixed with cold water, you can utilize a clamp thermometer and measure the temperature of the hot water pipe. Note that mixing before the point of use (unless the water is at least 120°F) increases the risk for Legionella. The farther from the point of use mixing occurs, the higher the risk.

    • If the hottest water at the tap is significantly below these temperatures, write down the fixture type (hot water only or hot/cold valve), and take a photo of any hot/cold mixing fixture under the sink. These are risk factors which alone may not cause Legionella but are important to be aware of. It is advisable to check with a plumber and/or the building manager to investigate and remediate low temperatures at the hot water tap.

Address requirement (b)(5): A list of critical control points (locations where actions to maintain relevant variables listed in (4) within performance limits are applied) within the project boundary

• The water management plan should include a list of critical control points. Control points are the locations where actions need to be taken if the control variables (i.e., temperatures and time to hot water) fall outside the desired range. Control points may include boilers, valves, pumps and any other part of the loop where a change (such as increasing temperature or flow) can be implemented. 

• For example, the control points that may need to be checked include: 

  • the boiler or water heater, to ensure that it is delivering water at the right temperature (usually 130-140°F),

  • the hot water pipe insulation, and/or 

  • the hot/cold mixing valves.

• If you are a tenant within a larger building, you may not be able to manage all the control points. If this is the case, ensure to document this in the management plan and describe the person who is responsible for the building control points (e.g., the building manager or building operations’ specialist).

Address requirement (b)(6): Verification and validation procedures for evaluating the suitability and proper implementation of the management plan. A Legionella sampling schedule is included if projects have operational control over cooling towers and spas

• The water management plan should include documentation stating a commitment to perform Legionella testing in the event that either: 

  • substantial evidence of Legionnaires’ disease cases arose among building occupants, and/or 

  • the hot water temperature cannot be managed. 

• Note that cooling towers and spas require Legionella testing, and maintenance of those fixtures should be addressed within a water management plan developed and implemented by a specialist.

7. Provide a template for ongoing management

Address requirement (b)(7): Protocols for documenting results of monitoring activities and corrective actions. If sampling for Legionella is planned, results are included

• The water management plan should provide a template of measurements and log of plumbers’ visits and tests. The template should also outline who is in charge of this task as stated in (b)(1) above. To maintain your WELL achievement milestone, this feature requires that proof of ongoing management be submitted annually. Ongoing management may be as basic as repeating the temperature tests, depending on your water management plan. As a reminder, the plan should include a recommendation to talk to a plumber or a building manager if the tests reveal that the water is no longer reaching the same temperatures compared with past measurements or if it takes unusually long to get hot.