Repair tips

Why Is My Toilet Leaking Water?

A leaking toilet is one of the most common calls we get, and most of the time the cause is smaller than people expect. Here's how to tell what's actually happening.

A toilet that's leaking usually falls into one of two categories: water running inside the tank that never fully stops, or water pooling on the floor around the base. They have almost nothing in common, and figuring out which one you're dealing with is the first step.

Running Water Inside the Tank

If you can hear water running periodically, or your water bill has crept up without an obvious cause, the problem is almost always inside the tank, not under the toilet. Two parts wear out the most:

  • The flapper: This rubber seal at the bottom of the tank degrades over time, especially with Stillwater's hard water, which runs around 8.5 grains per gallon. Mineral buildup keeps it from sealing fully, so water slowly leaks from the tank into the bowl and the fill valve keeps topping it off.
  • The fill valve: If the valve doesn't shut off completely, water keeps trickling into the overflow tube. You'll usually hear a faint hiss even when no one has flushed recently.

A quick test: add a few drops of food coloring to the tank and wait 15 minutes without flushing. If color shows up in the bowl, the flapper isn't sealing.

A Leak at the Base

Water pooling around the base of the toilet is a different problem entirely, usually the wax ring that seals the toilet to the drain pipe underneath. That seal degrades with age or shifts if the toilet has ever rocked slightly on an uneven floor. This kind of leak needs the toilet pulled to replace the ring, not a tank repair.

Why This Shows Up More in Stillwater

Hard water accelerates flapper wear faster here than it would in a place with softer water. Mineral scale builds up on the rubber and the seat it rests against, so a flapper that might last five years elsewhere sometimes needs replacing in two or three. If you've replaced a flapper more than once in the same toilet, that's usually why.

Is It Actually Wasting Water?

A running toilet can waste a surprising amount over a month, sometimes enough to show up as a real jump on your water bill even though nothing looks obviously wrong. If your bill has increased and you're not sure why, checking every toilet in the house with the food coloring test takes five minutes and rules out the most common hidden culprit.

When to Fix It Yourself vs. Call a Plumber

A flapper or fill valve replacement is a reasonable DIY job for most homeowners, parts run under $20. A leak at the base, a cracked tank, or a toilet that keeps failing after a flapper replacement is worth a professional look, since it may point to a drain line issue rather than the toilet itself.

Common questions

Good questions

Usually a flapper that isn't sealing fully or a fill valve that hasn't shut off completely. Both are common, inexpensive fixes.

Add food coloring to the tank and wait 15 minutes without flushing. If color appears in the bowl, the flapper is leaking.

Yes, a running toilet can waste a significant amount of water over a month, often enough to show up as an unexplained increase on your bill.

Hard water, around 8.5 grains per gallon here, leaves mineral scale on the rubber flapper and its seat, which shortens its sealing life compared to softer water areas.

Ready when you are

Toilet Still Leaking After a New Flapper?

If you've replaced the flapper and it's still running, the problem may be somewhere else. Call and we'll help you figure out where.

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