Water driven sump pumps use city water pressure to pump out your sump well when your primary electric sump pump fails to do so. The water driven sump pump uses approximately 1 gallon of city water to remove 2 gallons of water from your sump.
When the water driven sump pump is submerged, it creates a cross connection that can contaminate the public water supply if the flow of water is reversed during low pressure events such as a fire or water main failure, etc. A "reduced pressure principal backflow preventer" (or RPZ) meeting ASSE standard 1013 is required per state mandate at the plumbing immediately prior to the water driven sump in order to protect the public water supply. More information on backflow preventers and testing can be found under Cross Connection Information or by contacting Water Distribution at 989-837-6950.