Toilet Keeps Running? Causes, Quick Fixes & When to Call a Plumber
Why a running toilet matters
A toilet that keeps running can waste 200 or more gallons of water a day. In Colorado, where water rates climb every year, that is real money leaking down the drain. It also puts extra strain on your fill valve and can mask a bigger problem.
The 5 most common causes
- Worn flapper. The rubber flapper at the bottom of the tank hardens and stops sealing. This is the #1 cause.
- Fill valve set too high. Water rises above the overflow tube and spills into the bowl nonstop.
- Chain too short or tangled. It holds the flapper slightly open.
- Cracked or corroded flush valve seat. The flapper cannot seal against a rough surface.
- Failed fill valve. It never shuts off, especially in hard-water areas.
Quick DIY checks
Lift the tank lid. If water is spilling over the overflow tube, lower the float. If the flapper looks warped, replace it (they cost a few dollars). Put food coloring in the tank; if it shows in the bowl without flushing, the flapper is leaking.
When to call a plumber
If you have replaced the flapper and fill valve and it still runs, the flush valve seat may be damaged, or the toilet may be past its life. Our toilet repair team can fix it in one visit, or recommend an efficient toilet replacement that cuts water use by two-thirds.