Why Does My Toilet Run Then Stop Every Few Minutes?

If your toilet runs then stops every few minutes, even when no one has flushed it, the tank is slowly losing water.

When the water level drops slightly, the fill valve turns on briefly to refill the tank. Then it shuts off again. This cycle can repeat every few minutes.

The problem is almost always inside the tank and usually inexpensive to fix.

Why a Toilet Runs Intermittently

An intermittent refill cycle usually means water is leaking from the tank into the bowl.

The most common causes are:

• A worn or dirty flapper
• A small leak around the flush valve seat
• A faulty fill valve
• A crack or issue inside the tank

1) Worn or Dirty Flapper (Most Common Cause)

The flapper is the rubber seal at the bottom of the tank.

Over time it can:

• Warp
• Crack
• Develop buildup
• Stop sealing tightly

Even a slow drip will lower the tank water level enough to trigger a refill.

What to check:

• Remove the tank lid
• Add a few drops of food coloring into the tank
• Wait 10–15 minutes without flushing

If color appears in the bowl, the flapper is leaking.

Fix:

Replace the flapper. It’s inexpensive and usually takes less than 10 minutes.

2) Flapper Chain Too Tight

If the chain connected to the flush handle is too tight, it can prevent the flapper from sealing fully.

Fix:

• Make sure the chain has slight slack
• Adjust the hook if needed
• Flush and observe

3) Fill Valve Not Shutting Off Properly

If the fill valve is slightly misadjusted, it may cause small water fluctuations.

Signs include:

• Subtle hissing sounds
• Minor water movement in the overflow tube

Fix:

• Adjust the float to slightly lower the water level
• If the issue continues, replace the fill valve

4) Cracked Overflow Tube or Flush Valve Seat

Less common, but possible.

If the overflow tube is cracked or the flush valve seat is damaged, water can leak slowly into the bowl.

This usually requires part replacement.

When It’s Not a DIY Fix

Call a plumber if:

• The tank itself is cracked
• Water is leaking onto the floor
• The issue continues after replacing the flapper and fill valve

Most intermittent toilet refilling issues are solved with a simple flapper replacement.

Quick Recap

If your toilet runs then stops every few minutes, the tank is likely losing water slowly.

The most common fix is:

• Replacing the flapper
• Adjusting the chain
• Checking the fill valve

These repairs are usually quick and inexpensive.