CSLB C-36 Plumbing ContractorFixture and Appliance InstallationEasy
A client reports that their toilet is constantly running, and they've noticed an increase in their water bill. Upon inspection, the plumber observes a small, steady trickle of water flowing from the tank into the bowl. Which component is the MOST likely cause of this issue?
- AThe overflow tube.
- BThe flush lever.
- CThe fill valve.
- DThe flapper valve.
Show answer & explanationAnswer & explanation
Correct answer: D. The flapper valve.
A leaky flapper valve is the most common cause of a constantly running toilet. The flapper is designed to seal the drain hole at the bottom of the tank, and if it's worn or misaligned, water will continuously seep into the bowl.
Why the other options are wrong
- A. Water flowing into the overflow tube usually indicates an overfilling tank due to a faulty fill valve, not a direct trickle from the tank to the bowl when the tank isn't overfilled.
- B. The flush lever mechanism can cause the flapper to stay open if it's jammed, but the lever itself doesn't directly cause a trickle.
- C. A faulty fill valve typically causes the tank to overfill or not fill at all, not a constant trickle into the bowl from the tank.
Toilet Flapper Leak
A common toilet malfunction where the rubber flapper valve at the bottom of the tank fails to seal properly, allowing water to continuously seep into the toilet bowl.
- Causes a running toilet and increased water bills.
- Often due to wear, mineral buildup, or misalignment of the flapper.
- Can usually be repaired by replacing the flapper valve.
Memory trick: Flapper's flap, water's trap; if it's weak, the bowl will leak.