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Every so often we get a call from someone who reports their toilet flushing when nobody has used it. What is actually happening is the toilet tank re-filling as the water drains out of the tank and the water level gets low enough to trip the fill valve and the tank refills. This is called “Ghost” or “phantom” flushing and is usually a leak, the result of a worn rubber flapper that is allowing water to seep from the tank into the bowl and down the sewer. A poorly fitting flapper can waste a huge amount of water, and that can get expensive. An improperly adjusted flapper chain also could cause the problem.

“One big problem we find is left unchecked for long periods , a build up of minerals can occur in the drain pipe ( usually calcium and lime ) which could be hard as a rock and expensive to remove” says Todd Bloom, owner of “CONNECTIONS” a plumbing company in Houston TX.

Todd also pointed out that “we have seen several homes and business properties completely flooded from a ” soft stoppage ” in a toilet that had a bad flapper. For instance, the toilet is flushed, the user walks away not knowing the bowl is now clogged, water slowly leaks past the flapper into the bowl….tank refills, over and over until Monday morning and its noticed as the whole building is flooded because the water kept leaking into the bowl, but then overflowed because the bowl was clogged….what a mess.”

So how do you check for a leak?

One way to see if water is seeping from the tank is to conduct a simple dye test. Use food coloring or a powdered drink mix to noticeably color the water in the toilet tank.

1. Remove any sanitizing products from your toilet that may color the water.

2. Place the coloring agent in the tank.

3. The tank water will change color, while the toilet bowl water should be clear.

4. Wait ten minutes.

5. Check to see if any coloration appears in the bowl. If so, then you have a leaking flapper valve.

Plumbers caution do-it-yourself to make sure to get replacement flappers specifically intended for their toilets, because many so-called universal replacement kits simply do not fit well enough and can cause more harm than good.

After installing the parts, turn the water on and test-flush the toilet once or twice. If you replaced the flapper, perform the dye test again to ensure the flapper fits properly. Not all flappers fit properly in all toilets so you may still have a leak. You may wish to call a plumber.

Although not a particularly tough fix if caught in time, it’s never a bad idea to call a professionally licensed plumber to rid your house of this “ghost”.

A good plumber will usually replace the flapper and the fill valve at the same time. This will usually eliminate the problem. Then your plumber should also check the tank, the bolts and other parts of the toilet to make sure everything is working properly.

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