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 Los Angeles, CA 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 Los Angeles, CA

• One Star Inc · 742 S Hill St Ste 310, Los Angeles, CA · 12136221055
• Bill & Sons plumbing · 334 Main St, Los Angeles, CA · +12136423800
• Precision Emergency Plumber Los Angeles · 412 Colyton St, Los Angeles, CA · +12134516567
• Mr. Marcus Plumbing · 351 E Temple St, Los Angeles, CA 90012, United States, Los Angeles, CA · +13233287922
• Ok Plumbing, Inc. · 720 E 2nd St, Los Angeles, CA · 12136266211
• DL Plumbing · 1254 W 6th St # 700, Los Angeles, CA · (888) 487-3969
• Prime Leak Detection · 601 S Figueroa St # 4050, Los Angeles, CA · 18883401380
• Sun Trim · 2011 S Santa Fe Ave, Los Angeles, CA · 12136225066

Get free quotes from Los Angeles, CA 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.