Quick answer
A toilet that runs for a few seconds on its own, every few minutes or hours, is losing tank water into the bowl until the fill valve tops it up. This is called a phantom flush. Put food coloring in the tank and wait 15 minutes without flushing; color in the bowl means the flapper or flush valve seal is leaking. A refill tube pushed too far down the overflow can also siphon water out. A new flapper fixes most cases. HomeAdvisor puts typical toilet repairs at $150–$391. Call (888) 217-6781 to reach a plumbing company taking calls in your ZIP.
Follow the short menu, then your 5-digit ZIP. The line goes quiet for a few seconds while it connects; stay on. If it does not connect, call once more: companies taking calls change minute to minute.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed November 4, 2026· Next review May 2027
If you hear the toilet start refilling for a few seconds when nobody has used it, it is leaking water from the tank into the bowl. When the tank level drops far enough, the fill valve opens to top it up. Plumbers call it a phantom flush. It is a quiet, steady waste of water, and it is usually one inexpensive part.
Confirm It
Put a few drops of food coloring in the tank and do not flush for 15 minutes. If color shows in the bowl, water is leaking past the flapper or the flush valve seal. If the bowl stays clear but the toilet still refills, check whether water is reaching the top of the overflow tube, the open pipe in the middle of the tank.
Usual Causes
| What you find | Fix |
|---|---|
| Color in the bowl | Replace the flapper; match 2-inch or 3-inch to your flush valve |
| Flapper chain tight or caught under the flapper | Leave about half an inch of slack |
| Water level at or over the overflow tube | Lower the float on the fill valve |
| Refill tube pushed down inside the overflow tube | Clip it so it sits above the water; otherwise it can siphon the tank |
| Rough or chipped flush valve seat under the flapper | Replace the flush valve, or use a seat repair kit |
Flappers harden and warp with age and with in-tank chlorine tablets, which is why the problem often appears after a few years.
Talk to a plumber about this
One call reaches a plumbing company taking calls in your ZIP.
Why It Matters
EPA WaterSense counts toilets among the most common household leaks. A slow flapper leak is easy to ignore because the water goes down the drain unseen. If the bill has climbed, run the meter test in high water bill: how to find a leak.
What a Repair Costs
A flapper is a quick fix; a flush valve replacement needs the tank off and takes longer. HomeAdvisor puts typical toilet repairs at $150–$391. See toilet repair.
The Call
Call when a new flapper does not stop it, when the flush valve needs replacing, or when the shutoff valve behind the toilet will not close. (888) 217-6781 connects you to a plumbing company taking calls in your ZIP. Follow the short menu, enter your 5-digit ZIP and stay on while it connects; if it does not connect, call once more, because the companies taking calls change minute to minute.
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Frequently Asked Questions
Why does my toilet run by itself every few minutes?
Water is leaking from the tank into the bowl, usually past a worn flapper, so the fill valve turns on to refill the tank. The faster the leak, the more often it runs.
Is a phantom flush a big deal?
It wastes water every day and shows up on the bill. A flapper is an inexpensive part, so it is worth fixing promptly.
What if a new flapper does not fix it?
The flush valve seat may be worn or rough, or the water level may be reaching the overflow. A plumber can replace the flush valve, which needs the tank off.
Sources
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
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