What Makes a Toilet Run For No Reason

Out of the blue, the toilet begins to run and it doesn’t stop. You cannot find a reason for the toilet to be running. What could make a toilet just start to run for no reason?

A toilet that is running is providing symptomatic evidence that there is something wrong somewhere. There is always a reason for a running toilet. It just hasn’t been found yet. Here is what you’ll want to look for to solve the problem.

1. Dealing with the phantom flush.

If the toilet turns on and off by itself, like it has been flushed, then this is your problem. The cause is a slow leak between the toilet tank and bowl. You’ll want to drain the bowl, remove the water from the tank, and then clean the flapper seat. If the flapper is damaged or worn out, replace it.

2. Stopping the water trickle.

If the toilet sounds like it is hissing, then there is a supply line issue. You have water coming through the inlet valve. You’ll need to check the refill tube, the inlet valve assembly, and the float and float valve to ensure nothing is sticking or needs an adjustment.

3. Stuck with a weak flush.

Sometimes, a toilet begins to run because there is an obstruction in the flush holes underneath the rim of the toilet. This causes the bowl to empty too slowly, creating a weak flush. You will want to remove any debris, calcification, or scale from the flush holes to solve this problem.

In most situations, there will be an issue with the fill valve that must be resolved. The easiest way to stop a running toilet in this situation is to install a new fill valve. Turn off the water supply, flush your toilet, and then remove any remaining water from the tank. Then disconnect the supply line, unscrew the lock nut on the fill valve, and lift it out.

The new fill valve will come with specific installation instructions to follow. You can hand-tighten the lock nut, but make sure to turn it one more time with an appropriate tool. If your overflow pipe is higher than the critical level mark on the new fill valve, you’ll need to shorten the pipe to match. A simple hacksaw will usually get the job done.

Toilets always have a reason why they are running. Check the flapper and replace if necessary. Then follow the other steps to ensure you’re not wasting water because your toilet won’t stop running.

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