The toilet has been running since this morning. You've jiggled the handle. It stopped for about 10 minutes. Now it's running again. How bad is this, and do you need to call a plumber?
Most of the time: no. Nine out of ten running toilets are a worn flapper, a misaligned flapper chain, or a failed fill valve — all cheap parts available at any hardware store. But there are a handful of scenarios where the fix isn't that simple, and knowing which one you have before you spend money (or time) on the wrong solution matters.
How to Diagnose a Running Toilet in 2 Minutes
Take the Lid Off the Tank
Remove the toilet tank lid and set it somewhere safe. Look inside. The water level should be about an inch below the top of the overflow tube (the open vertical pipe in the middle of the tank).
Is Water Running Into the Overflow Tube?
If you see water flowing into the top of the overflow tube and down into the bowl, the float is set too high or the fill valve is allowing too much water in. This is a fill valve or float adjustment — usually a $10–15 fix.
Is the Tank Level Normal But the Toilet Still Runs?
If the water level looks normal and water is still running into the bowl (you'll hear it), the flapper isn't sealing. This is the most common running toilet cause — a warped, worn, or mineral-coated flapper that isn't making a watertight seal against the flush valve seat.
The Food Coloring Test for Flapper Leaks
Put a few drops of food coloring in the tank (not the bowl). Wait 15 minutes without flushing. If color appears in the bowl, the flapper is leaking.
The $12 Fixes: Do These Yourself
| Problem | Fix | Typical Cost |
|---|---|---|
| Worn or warped flapper | Replace flapper — match the brand (Kohler, American Standard, etc.) for best fit | $5–15 |
| Flapper chain tangled or too short | Adjust chain length so there's about 1/2 inch of slack when the flapper is closed | Free |
| Float set too high | Bend the float arm down slightly (old ball float) or adjust the float cup height on newer fill valves | Free |
| Worn fill valve | Replace fill valve — universal fit valves work for most toilets | $10–20 |
One northeastern NC specific issue: In homes with hard well water, mineral deposits can coat the flapper and the flush valve seat — preventing a proper seal even with a brand new flapper. If you've replaced the flapper twice and the toilet still runs, the flush valve seat needs to be cleaned or replaced — that's a plumber call.
When to Call a Plumber: These Aren't $12 Fixes
- Water on the floor around the toilet base — not a tank problem. This is a wax ring failure or a cracked toilet base. Continuing to use the toilet will damage the subfloor. Call (252) 666-9003.
- Toilet rocks when you sit on it — the toilet is loose on the flange, which can break the wax seal. Left alone this leads to floor damage and a more expensive repair.
- You've replaced the flapper twice and it still runs — the flush valve seat is damaged or scaled from hard water and the flapper cannot seal against it properly.
- Toilet fills extremely slowly — low water pressure or a supply line issue, not a tank component problem.
- The tank won't fill at all — the shutoff valve may be partially closed or the fill valve may have completely failed.
What Running Toilets Actually Cost You
A toilet flapper that leaks at a slow trickle wastes approximately 200 gallons of water per day — about 6,000 gallons per month. In Elizabeth City on city water, that's roughly $30–50 added to your monthly water bill for a problem that costs $8 to fix.
A faster leak — one you can hear constantly — can waste 500 gallons or more per day. That's a $100+ monthly water bill impact from a $12 flapper.