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How to Fix a "Ghost Flushing" Toilet

Why is My Toilet Flushing By Itself?

Here at Henry Bush Plumbing, we have had more than a few customers state that their toilet is flushing by itself. Some folks go as far as to suggest they think they have a ghost. Actually, this is not an uncommon problem with toilets and, contrary to some beliefs, the explanation and resolution are far from the paranormal.

Toilet repair

What to check if your toilet is ghost flushing

Back Siphonage

In most cases, there will be a small tube coming from the fill valve to the flush valve, which is located in the center of the tank. If this tube, called the refill tube, is inserted too far into the “overflow” tube of the flush valve, water will likely siphon from the tank and down this tube, causing the water level to drop in the tank.

To properly solve this problem - re-position the end of the refill tube to the top of the overflow tube of the flush valve with an appropriate fastening clip. With the end of the refill tube above the water level inside the tank, the possibility of back siphonage has been eliminated.

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High Water Level

If the water level in the tank is above the top of the overflow tube (located on the flush valve), then the fill valve will either continuously run or cycle on and off.

Resolve this problem by adjusting the water level on the fill valve to a point approximately 1/2″ to 1″ below the top of the overflow tube (see fill valve manufacturer for adjustment procedures).

Note that for toilets where the tank and the bowl are one molded piece, in lieu of a smaller refill tube, a larger “rim wash” tube, approximately 3/4″ in diameter, will be installed from the fill valve to the back of the bowl. The water level in the tank needs to be adjusted to a level below that of the insertion point of where the rim wash tube enters into the back of the bowl.

Flapper/Tank Ball

The flapper and/or the tank ball are some of the more common culprits of "ghost flushing". They are both located on the flush valve, which is usually located in the center of the tank. Check the flapper/tank ball at the bottom of the tank. The flapper/tank ball is connected to the tank lever with either a strap, a chain, or maybe a brass wire, and is located at the bottom of the tank.

To check the flapper/tank ball - rub your finger along its edge. If, due to deterioration, the material of the flapper comes off on your finger, we know at this time the flapper/tank ball needs to be replaced. In some other cases, this seal may be located at the bottom of a column located at the center of the tank. Either way, it is this seal that holds the water inside the tank up, until someone presses that lever. So whether it is a flapper, tank ball, or some other type of seal, if the material comes off on your finger when you touch it, it needs to be replaced.

One last thing regarding this seal: some of the materials used can be a polyurethane material in which case, even if the device has failed, the material will not come off on your finger. To check this type of seal, the device must be removed and visually inspected. The seal should be flat and without any ripples. If you see a ripple on the bottom side of the seal, replace it with a new replacement seal of a similar type.

When replacing a flapper, be sure to pay attention to the adjustment in length of the chain, strap, or brass wire. An adjustment that is too short will create a symptom where water either continues to run or the fill valve will “ghost flush”. An adjustment that is too loose will create a symptom where the tank level will need to be held down for the entire cycle of the flush because it does not lift the flapper/tank ball up high enough in order to allow it to float.

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Water Pressure

High water pressure conditions can cause a good fill valve to act as if it is not functioning properly. The call we often get is one where a customer has replaced their old fill valve with a new one, they replaced their flapper, they have adjusted the water level below the overflow tube, they mounted the refill tube to the overflow tube with the supplied clip, and the new fill valve still cycles on and off. “High water pressure,” we tell them with assurance.

What happens here is after a pressure regulator has failed, the water pressure in the house increases to full city-supplied pressure when no other water is in use. We call this “static” pressure. Throttling the valve down at the main water shutoff will not solve the problem, because at a static water pressure condition (without any water being used in the house), the pressure is just as high as if you had the valve closed off to the level of a drip.

To clarify, by throttling the main valve down you have adjusted “volume”, not “pressure”. Adjusting the pressure regulator at this point will not solve the issue either. A residential water pressure regulator, when functioning properly, will not exceed 80psi. Therefore, if the water pressure is above this point, we know at this time the regulator has failed and needs to be either replaced or rebuilt.

To confirm the water pressure condition, you will first need a water pressure gauge, a commonly stocked item at our Redlands Showroom and Warehouse supply. With the Pressure gauge connected to a hose bib location, after the incoming water supply to the house and after the existing pressure regulator, turn the hose bib on in order to read the water pressure at this point. Keep in mind that we are looking at checking the regulated pressure after the existing pressure regulator.

With the pressure gauge reading the “static” water pressure, assuring there is not any water in use at this time, record this reading. While monitoring the pressure at the gauge, have someone flush the toilet in question. The water pressure will likely drop to a point below the set pressure of the existing pressure regulator, usually between 50 and 75 psi, (even with a faulty pressure regulator). When the toilet attempts to shut down, looking at the water pressure gauge, you will see the water pressure rise to just below that of the level of incoming water supply pressure. At this point the fill valve of the toilet will be forced to relieve the excess pressure at which time you will see the pressure on the gauge drop down, due to the relief of excess pressure when the fill valve is forced to turn back on, and the cycle will then keep repeating itself until the fill valve has reached the point where it can shut down at the full city supplied pressure.

With exception to the flapper/tank ball test, because of the direct relation of water pressure to the fill cycle of the toilet, it is suggested that you perform this pressure test before any of the other attempted diagnostics, in order to avoid the unnecessary replacement of any of the toilet parts.

With the exception of a faulty fill valve or high water pressure condition, we have pretty much covered the solutions to a running water condition. If after checking all of the other conditions the fill valve continues to leak water, the fill valve will need to be replaced. Follow manufacturer guidelines in order to properly install the new fill valve.

Call Henry Bush Plumbing for Prompt Toilet Repair in Redlands

We hope you found this information helpful for diagnosing and troubleshooting your ghost flushing toilet. If you are in need of additional help, please do not hesitate to contact Henry Bush Plumbing Heating and Air Conditioning to schedule a service call. We are available 24/7 to respond to emergencies and can be contacted online or at (909) 315-4779.