Backflow Preventer
A backflow preventer is a device that keeps water from flowing backward through the plumbing, protecting the clean supply from contamination if pressure drops or reverses.
Water is supposed to flow one way, from the supply into the home. But a sudden pressure drop, such as a water main break or heavy fire-department draw, can reverse that flow and pull used or contaminated water back toward the clean supply. A backflow preventer stops this with internal check valves and, in higher-hazard devices, relief ports that dump rather than let water reverse.
These devices appear wherever there is a credible path for contamination to be siphoned back: irrigation systems, boilers, fire sprinkler lines, and the connection between a private well and a municipal supply. The right type depends on the hazard level, from a simple vacuum breaker on a hose bib to a reduced-pressure (RPZ) assembly on a commercial or irrigation line.
Because they protect public water, many jurisdictions require certain backflow preventers to be tested by a certified tester every year. A failed test means the assembly must be rebuilt or replaced before it is put back in service.
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- Plumbing Permit : A plumbing permit is official authorization from a local building department to perform plumbing work, paired with one or more inspections to confirm the work meets code.
- Rough-In Plumbing : Rough-in plumbing is the stage where all the supply and drain pipes are run inside walls and floors but no fixtures are connected yet, completed before the walls are closed up.
- Fixture Unit (DFU) : A fixture unit is a code unit of measure that rates how much water a fixture supplies or drains, letting designers size pipes and vents for the combined demand of a building.
- Wet Vent : A wet vent is a code-approved arrangement where a single pipe serves as both the drain for one fixture and the vent for another, reducing the number of separate vent lines needed.