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Toilet running or won't flush: NYC fixes for tank and flushometer toilets

A leaking toilet is one of the most common reasons for a high water bill. DEP says water can flow through an open fill valve at three to five gallons a minute, up to 4,000 gallons a day. The good news: most causes are simple parts.

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Test for a silent leak (DEP's method)

1. Put one teaspoon of food coloring (or a dye tablet) in the tank.
2. Wait 10–15 minutes without flushing.
3. Color in the bowl means water is leaking from the tank into the bowl. The faster it shows up, the bigger the leak.

Flapper or fill valve?

DEP's trick: mark the water line in the tank with a pencil, flush, and watch it refill.

• Water rises above the mark and then goes down: probably a flapper leak. Flappers warp over time, and DEP notes that in-tank chlorine cleaners can corrode them.
• Water rises to a point below the mark and then creeps above it: probably a faulty fill valve.
• Also check that the chain or trip lever still lines up, so the flapper seals.

Replacing a flapper or fill valve is a common DIY job if you're comfortable. Close the valve behind the toilet first. DEP's tip: don't replace an old float-ball fill valve with another float-ball valve; use a newer piston-type valve.

Flushometer toilets (no tank)

DEP says about 30% of residential toilets in NYC have no tank and use a flushometer valve on a pipe from the wall. If you see water moving in the bowl after a flush, the valve is leaking and needs repair or replacement. "Phantom flushes" caused by building pressure changes should be checked by a licensed plumber. After the water's been shut off, flush once or twice to clear air out of the valve.

Weak flush or won't flush

• Tank water level set too low, or a chain with too much slack.
• A partial clog: try a flange plunger, not a flat sink plunger.
• If several fixtures gurgle or back up together, it may be a drain line or building stack problem. See clogged drain in NYC.

Questions

Sources

• NYC DEP: Toilet Leak Detection

Rules and phone numbers can change. Check the official source before relying on them.

Related guides

• Clogged drain in NYC: what to try, and when it's a building problem
• Leak under the sink in Manhattan: find it, stop it, get it fixed
• Need an emergency plumber in Queens? Do this first
• All NYC home repair guides