ASHRAE 188 water management, with control points measured all year
ASHRAE 188 sets minimum requirements for managing Legionella risk in building water systems. It asks for a program team, a description of the water systems, a hazard analysis, control locations with limits, monitoring, corrective actions and documentation. Aqueduct supplies continuous measurements at control points, such as water temperature, flow and stagnation, with excursions flagged. Your program team runs the plan.
What ASHRAE 188 is and who it applies to
ANSI/ASHRAE Standard 188, Legionellosis: Risk Management for Building Water Systems, sets out what a water management program must contain. It covers potable hot and cold water, cooling towers and evaporative condensers, decorative fountains, spas and other systems that can grow and spread Legionella. The standard identifies the buildings and conditions that call for a program, and healthcare facilities usually fall within it. ASHRAE Guideline 12 gives practical guidance on implementation.
In the United States, the CDC publishes a widely used toolkit for developing a water management program, and CMS expects certain healthcare facilities to have water management policies in place. The program is a living process: describe the system, find where hazards can occur, set control limits at those points, monitor them, act when they drift and confirm the program works. Requirements and expectations change between editions and agencies, so check the current versions that apply to your buildings.
ASHRAE 188 program elements and the evidence Aqueduct supplies
Aqueduct supplies measured control point data. Your program team owns the plan, sampling and decisions.
| Requirement | Evidence needed | How Aqueduct supplies it |
|---|---|---|
| Program team | Named people responsible for the program | Alert routing by role so the right person sees each excursion; the team itself stays in your plan |
| Water system description | Flow diagrams showing supply, storage, heating, distribution and outlets | The WaterGuard digital twin shows the metered system block by block, a useful companion to your process flow diagram |
| Hazard analysis | Where conditions could support growth: stagnation, temperatures in the growth range, low disinfectant | Flow and temperature history that shows low-use branches and temperature drift, where sensors are fitted |
| Control locations and limits | Defined points, each with a limit to hold | Each control point modeled in aQ Core with its own limit, judged reading by reading |
| Monitoring | Records that control measures were checked at the planned frequency | Continuous logging at instrumented points, so records exist between manual rounds |
| Corrective actions | What was done when a limit was missed | Excursion alert, work order in your CMMS and the reading that confirmed recovery, kept as one event |
| Verification and validation | Proof the plan is followed and that it works | Trend reports by control point and period to sit next to your sampling and lab results |
| Documentation | Records kept and retrievable for review | Exports by point, building and date range, with device health shown |
How to prepare your water management program for review
Confirm scope and team
Use the ASHRAE 188 screening questions and your regulator's guidance to confirm which buildings need a program, then name the team and its roles.
Describe the system
Draw or update flow diagrams for each building. Where Aqueduct is metering the water system, compare the twin with the drawings and fix what has changed.
Instrument the control points
Fit temperature and flow sensing at heaters, return loops and representative outlets the hazard analysis names, or read existing BMS points.
Run monitoring and corrective action
Let continuous data catch drift between manual rounds. Every excursion should close with an action and a confirming reading.
Verify and review
Review trends next to sampling results with the team at the interval your plan sets, and update the plan when the building or its use changes.
What stays with your program team
A water management program is people and decisions. Sensors make it easier to prove.
Sampling and lab testing
Legionella sampling, disinfectant residual testing and lab analysis stay with your team and your accredited lab.
Remediation
Flushing, thermal or chemical disinfection and plumbing changes are decided and done by your team and contractors.
The plan itself
The written program, its hazard analysis and its approval belong to your team. Aqueduct does not certify any water system.
Related standards and guidance
Often used together with ASHRAE 188.
sites in 21 countries run on Aqueduct.
and 9 clinics in one of India’s top hospital chains.
US airport running water intelligence on Aqueduct.
of commercial real estate under Aqueduct.
FMCG manufacturing campus.
operations run on Aqueduct.
Related
Common questions
ASHRAE 188 is the standard for Legionellosis risk management in building water systems. It requires a water management program with a team, system description, hazard analysis, control limits, monitoring, corrective actions and documentation. Aqueduct supplies continuous measurements at the control points.
No. The standard requires monitoring at a frequency your program defines, which many teams meet with manual rounds. Continuous sensing adds records between rounds and catches drift sooner.
Programs commonly monitor water temperature, flow or use at low-traffic outlets and disinfectant levels. Aqueduct logs temperature and flow where sensors are fitted; disinfectant testing usually stays with your team.
No. Sampling and lab analysis remain the way to confirm the program works. Aqueduct supplies the operating data that helps explain the results.
No. ASHRAE 188 is a consensus standard, while the CDC toolkit is practical guidance for building a program. Many teams use both.
Where flow is metered on branches, Aqueduct shows low-use and no-use periods, which helps your team target flushing. It cannot see unmetered dead legs.
See Aqueduct on your own facility.
Bring a site, a utility bill or a question. We will show you where the loss is.