This problem is almost certainly caused by a bad flapper or flapper seat. The solution is to drain the tank and bowl, check and clean the flapper seat and then replace the flapper if it's worn or damaged.
If your toilet randomly runs off and on for a few seconds, it is likely due to a broken flapper. While the flapper is supposed to drop down and re-seal the tank when enough water has gone through, a cracked or decaying flapper will allow water to keep flowing through and run periodically.
Why My Toilet Randomly Runs? There are plenty of reasons why your toilet could be non-stop running, but here are some of the most common: Your chain could be too short, keeping your flapper from fully sealing to its seat. Your flapper may be damaged or dirty, preventing it from sealing properly.
Flapper problems are the most common cause of running toilets. To attempt to fix the problem fast, turn off the toilet water, remove the flapper, and wash and scrub its plastic cap and stopper thoroughly. Put the flapper back when you're done and try to fit it over the hole as snugly as possible.
Check the Chain
A constantly running toilet is typically due to an issue with the flush valve assembly, so one of the first parts to inspect should be the chain and flapper. If the chain is too short, then it won't allow the flapper to close properly.
Among the most common problems for a running toilet is caused by a fill valve issue. This is when the water level is too high and water spills out of the top tank and into the overflow tube then down into the toilet bowl. This happens when there is excess water in the top tank.
There is also an overflow tube inside your toilet tank to ensure there is never too much water in the tank. After a flush, the typical toilet takes between 10 and 15 seconds to refill and stop running.
Sometimes toilets make strange noises like gurgling, screaming, hissing, etc. These noises are mostly related to the movement of air or water. If the toilet hisses, it is probably because water or air is leaking from the fill valve. In any case, if the valve is not shutting properly, the toilet may leak.
Check the Overflow Tube Height
If the overflow tube is too short, causing the water to run continuously, you'll need to replace the flush valve assembly with a compatible flush valve. However, if the overflow tube is the right height for the toilet, the water level or the fill valve might be the issue.
Your toilet may be constantly running because of a faulty flapper seal. One of the most common causes of a flapper seal breaking is improper installation. Human error is often to blame for this issue, but some design flaws in older toilets can cause the same problem.
This can be a frustrating problem for homeowners or businesses to deal with since it can cause a rise in utility costs. It can also be a sign of an external water leak that could cause water damage if it is not taken care of quickly.
Ideally, the water level in the toilet tank should be 1 to 1.5 inches below the top of the overflow tube (also called an overflow pipe), an open-ended tube centrally located in the tank. When the water level is too high, water will constantly drain from the fill tube into the overflow tube, causing a running sound.
Some drop-in bowl cleaners are also hard on the rubber component of a flapper. As the flapper deteriorates it allows leakage. Although it is not something many of us think of as needing replacement on a routine basis, in general, a toilet flapper should be replaced every three to five years.
If you've tried replacing the toilet flapper but the toilet still runs, the flush valve seat is probably rough or pitted. You can replace the entire flush toilet flapper valve, but it's a big job.
The most common toilet leak is caused by a deteriorated flush valve (flapper) at the bottom of the toilet tank. If the flapper does not seat properly, water will leak into the toilet bowl. Often this leak will occur without being heard.
According to Fixr, the average toilet valve repair cost is between $75 and $200 to replace a flush valve or up to $400 to fix a constantly running toilet. This includes the cost of the plumber's time for the toilet repair and the cost of the toilet parts.
Will a running toilet stop eventually? As fresh water enters the tank, a mechanism eventually shuts off the water flow and the toilet will stop running. However, when things go wrong with the valve, flapper or overflow then it's best to get it sorted.
Ignoring the loud noise may lead to burst pipes- you will need to install a water hammer arrestor on the water line to stop your toilet from making a noise like that. You can also reduce the flow by adjusting the shut off valve, so the water pressure is lower and less likely to cause strange noises.
A toilet makes a hissing sound when the chain prevents the flapper from closing or when the chain is so long that excess chain gets caught under the flapper. A chain that is too short will keep the flapper in a slightly raised position, allowing water to pass out of the tank—creating a toilet hissing sound.
Toilets are designed to efficiently empty the contents of the bowl through a downward motion into the drainpipe, but the force of the flush cycle also creates a fine spray of particles in the air. Those particles easily spread when a lid is left up during flushing.
A running toilet can quickly turn into a flooding toilet. If you have a septic tank, all of that excess water risks flooding the tank, which can lead to the saturation and failure of your drain field.
In general, a single flush 1.6 gpf or 1.28 gpf toilet tank will take around half minute (30 seconds) to one minute (60 seconds) to fill.
Toilet Flapper Causing Ghost Flushing
Typically, the flapper no longer creates a seal over the drain, so water continuously fills the bowl until causing it to flush, preventing it from overflowing. Simply replacing the flapper normally fixes the problem.