Low-Pressure Events: Variation in State Regulations and Utility Practices

Distribution system operation and maintenance is an integral component of the multiple-barrier approach to providing safe drinking water. Low-pressure events have the potential to affect public health by allowing contaminants to enter the distribution system. Existing waterworks standards, state guidelines, and state regulations describe minimum pressure standards and best practices to reduce contamination risk when low-pressure events occur, but no federal regulation directly addresses low-pressure events. A study was conducted to survey state minimum pressure standards as well as utility practices related to low-pressure events. While most states have a minimum pressure standard of 20 psi, policies for when to report events to state primacy agencies and when to issue boil-water advisories vary. Federal guidance could potentially make handling of low-pressure events more consistent, but more research is needed to quantify to what extent more consistent practices could improve public health.