Why Is My Toilet Running?
A running toilet is usually caused by a faulty flapper, a float set too high, or a worn fill valve. A constantly running toilet can waste 200+ gallons of water per day, significantly increasing your water bill. Most flapper issues are DIY-fixable for under $15, but persistent problems may require valve replacement.
Common Causes
Faulty Flapper
The flapper is a rubber seal at the bottom of the tank that holds water until you flush. Over time, it warps, cracks, or collects mineral deposits, allowing water to leak into the bowl continuously.
Float Set Too High
The float controls the water level in the tank. If set too high, water continuously drains into the overflow tube, causing the fill valve to run constantly.
Worn Fill Valve
The fill valve refills the tank after each flush. When it wears out, it may not shut off completely, causing water to run continuously or cycle on and off.
Overflow Tube Issues
If the overflow tube is cracked, too short, or improperly positioned, water may continuously drain from the tank, triggering the fill valve to keep running.
Mineral Buildup
Phoenix's hard water leaves deposits on flappers, fill valves, and other components. This buildup prevents proper sealing and can cause intermittent or continuous running.
Chain Problems
The chain connecting the flush handle to the flapper can be too long (causing tangles), too short (holding the flapper open), or tangled, preventing proper flushing.
What Should You Do?
Try This First
- Remove the tank lid and check if water is flowing into the overflow tube (float is too high)
- Inspect the flapper for cracks, warping, or mineral buildup, replace if damaged ($5-15 part)
- Check that the chain has about 1/2 inch of slack and isn't tangled
- Adjust the float to lower the water level to about 1 inch below the overflow tube
- Clean mineral deposits from the flapper and valve seat with vinegar
Call a Pro If...
- You've replaced the flapper but the toilet still runs
- The fill valve won't shut off even with float adjustments
- You hear hissing sounds from the tank
- The toilet runs intermittently (phantom flushes)
- There's water on the floor around the toilet base
- You're not comfortable working with toilet components