Quick answer
- Check the chain
- Check the flapper
- Check the water level
Pro tip
Do a quick "dye test": put a few drops of food coloring in the tank. If color shows in the bowl after 10-15 minutes, you likely have a flapper leak.
Common causes
- Flapper not sealing
- Fill valve set too high
- Chain too tight / tangled
5-minute fixes
1. Check the chain
If it is too tight, it can keep the flapper from closing.
2. Press the flapper down
If it stops running, the flapper likely needs replacement or reseating.
3. Check water level
Adjust the fill valve so water stops below the overflow tube.
When to call a plumber
- You replaced the flapper and it still runs
- The fill valve will not shut off
- You see water around the base of the toilet
