Why does my toilet keep running?
A toilet that runs constantly — or refills on its own every few minutes — is almost always a worn flapper or a faulty fill valve inside the tank. It's a small part failing, but a big water bill: a running toilet can waste 200+ gallons a day. The parts cost $10–$25, and this is the most DIY-friendly plumbing fix there is.
Likely causes
- Worn flapper — The rubber seal at the tank bottom warps with age and chlorine — water seeps into the bowl silently.
- Faulty fill valve — The toilet runs on after flushing or the valve hisses — the shutoff mechanism is worn.
- Chain or handle problem — A chain that's too long or kinked holds the flapper open.
- Cracked overflow tube — Water spills into the overflow — less common, needs a new flush valve assembly.
What you can check yourself
- Drop food coloring in the tank: if color appears in the bowl without flushing, the flapper leaks. Replace it — a 15-minute job, mostly no tools.
- Check the water level: it should sit about an inch below the overflow tube; adjust the fill valve if water spills over.
- Jiggle test first: if jiggling the handle stops the running, it's the chain or flapper alignment.
Typical cost
DIY parts run $10–$25. A plumber in Washington, DC typically charges $150–$350 for the repair visit; full toilet replacement runs $350–$700 installed.
When to call a pro
Water on the floor at the base, a toilet that rocks, or a sewer smell — that's a wax-ring or flange problem, not a flapper. Call before the subfloor rots.
Plumber pros in Washington, DC
- Spartan Plumbing, Heating And Air Conditioning · 1776 I St Nw Ste 900, Washington, DC · 12025590339
- Plumbers 911 Washington DC · 1915 I St NW Ste 200, Washington, DC · 8779325325
- Greenpipe Biotech Inc · 1629 K St NW, Washington, DC · +12027192525
- Grayton Plumbing · 15 O St SW, Washington, DC · 2025444366
- MM Remodeling · 2067 Park Rd NW, Washington, DC · +12024153808
- Plumber In DC · 620 Park Rd NW, Washington, DC · 2028100624
- Plumbline Plumbers · 1629 A St NE, Washington, DC · 2025439515
- District Plumbers · 2300 4th St NE, Washington, DC · 12024995726
Get free quotes from Washington, DC pros →
Data by Servik — verified local pros from official license records and public sources. Cost figures are typical ranges, not quotes; a pro's written estimate is the real number.