Group B Public Water Systems—Disinfection

Emergency Disinfection

A Group B water system should disinfect if it experiences any of the following:

  • Your water system loses pressure for any reason.
  • You open up any part of the water system for maintenance or repairs.
  • Backflow or back-siphonage creates a cross-connection event.
  • The water system experiences two or more Coliform detections within a short period of time.

Notify your customers first

If you don't normally disinfect your water, notify all your customers first. Water with high levels of chlorine can seriously affect people with unique medical needs, such as kidney dialysis patients. All water systems should maintain a list of such customers. People with aquariums or ponds that contain fish will also be especially interested in knowing that the water is to be chlorinated.

Disinfecting a well, pressure tanks, storage tanks, and distribution system without a storage tank

Please refer to Emergency Disinfection of Small Water Systems 331-242 (PDF) for proper steps to disinfect various water system configurations.

Contact our nearest regional office from 8 AM to 5 PM, Monday through Friday. If you have an after-hours emergency, call 877-481-4901.