With the exception of limited re-openings of the Highlander Pool Fitness Center, the Library and Playgrounds, City buildings are closed to the public.  Phase 2 Updates .

Backflow Prevention

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Backflow Prevention

In accordance with the US EPA Safe Drinking Water Act, and the Florida Administrative Code Section 62-550, the City of Dunedin has installed BACKFLOW PREVENTION DEVICES on the water service lines to protect the public water system. This notice is to advise you of a possible situation that you may experience.     




When a Backflow Prevention Device is NOT present, the public water mains provide a ”cushion” that absorbs pressure that occurs in a home’s plumbing system from thermal expansion. This water expansion is caused when water is heated in the hot water heater. The Backflow Prevention device is designed to stop water from back flowing into the City main. Therefore, the expanding water no longer has a place to go so it remains in the hot water heater and builds up pressure. In normal hot water heater operation the thermal expansion would cause the TEMPERATURE & PRESSURE CONTROL VALVE (TP) to release water when the pressure exceeds 100 lbs. per square inch (PSI). Discharge may occur indicating the mechanism working properly.  Discharge will occur in the immediate area surrounding your hot water heater if a discharge line does not extend from the pressure control/valve on your hot water heater through an outside wall. The following devices can be installed by a plumber to prevent this:

  1. Ball cock relief valve – Watts governor 80 or equal
  2. Temperature and pressure relief valve installed on an out side spigot, set at 90 P.S.I. – Watts model 530 or equal
  3. Thermal expansion tank
If you have any questions or if your plumber has questions, please call Dan Chislock at the City of Dunedin Water Division (298-3100).

For more information on Thermal Expansion click on the links below.

Learn more about Thermal Expansion