CSLB C-36 Plumbing ContractorFixture and Appliance InstallationEasy
A homeowner reports that their toilet is constantly running, and they've noticed a significant increase in their water bill. Upon inspection, the plumber observes a slow, continuous trickle of water into the toilet bowl, even when the tank is full. The fill valve appears to be functioning correctly, but the flapper is worn and does not seal properly. Which component is the most likely cause of the continuous running and increased water bill?
- AThe toilet's shut-off valve.
- BThe toilet's siphon jet.
- CThe toilet flapper.
- DThe toilet's fill valve.
Show answer & explanationAnswer & explanation
Correct answer: C. The toilet flapper.
A worn or improperly sealing flapper allows water to continuously leak from the tank into the bowl, causing the fill valve to cycle on and off to refill the tank, leading to a constantly running toilet and wasted water.
Why the other options are wrong
- A. The shut-off valve controls water supply to the toilet and wouldn't cause continuous running if open.
- B. The siphon jet is part of the bowl's flushing mechanism and doesn't directly cause continuous running from the tank.
- D. The scenario states the fill valve appears to be functioning correctly, refilling the tank as water leaks out.
Toilet Flapper Leak
A common cause of a running toilet where the rubber or plastic flapper, which seals the tank's drain opening, fails to create a watertight seal, allowing water to continuously leak into the bowl.
- Prevents water from staying in the tank.
- Often becomes worn, brittle, or misaligned.
- Causes fill valve to constantly refill tank.
Memory trick: Flapper's flap means water will lap.