Sorry for basic questions...Newbie here. Recently got a high water bill and eventually found out that the basement toilet is randomly leaking. Basically running toilet i.e. water leaking from the flush tank into the toilet seat. If I shut off the water supply valve there is no leak. No outside water leak on the floor.

Upon plumber visit, he mentioned that problem is due to pressure caused by wrong rough in size. He mentioned that earlier person installed a 12" toilet in 10" rough space which is leading to higher pressure. He suggested to buy a new 10" toilet. Earlier installed toilet is a brand new one installed just 1 year back and hardly used 5 times as it is in the basement.

Somehow I don't feel right as leak doesn't happen when the valve is shut off even when there is water in the flush tank. Leak happens only when water supply valve is opened.

I am selling my house and need to fix it immediately. I need a good solution to avoid any problems for the new owner.

Appreciate your help.



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i haven't laughed so hard in weeks...
a 12 inch rough toilet will not fit in a 10 inch rough space...
get another plumber...

some will if it is not exactly 10", but whether that is the real problem or not is something we would have to be there to check.

Not a plumber just a DIYer here.

I think you need a different plumber.

Your symptons are: (1) water leaks from tank into bowl (2) no outside leak the floor is dry (3) if you shut off the supply valve the leak stops.

I am thinking your fill valve is not shutting off completely. The fill valve is the vertical stem inside the tank that connects to your supply hose at it's base. Usually there is a floating thingie around the shaft or it may be a balloon thingie with a lever, that floats up as the water fills the tank, and when water reaches a certain level, that shuts off the filling.

If the flush valve is leaking, the leak would be continuous and turning off the supply valve would not do anything to stop it. You will see continuous slow trickle of water from tank to bowl.

If the fill valve is not shutting off completely, then the water in the tank continues to rise and would have overflowed outside of the tank if not for the overflow tube that takes that rising water into the bowl. Shutting off the water supply stops the filling of the tank and stops the "leak".

Sometimes it is not the shut off mechanism gone bad. Sometimes the overflow tube is too low in relationship with the intended tank water level. If the overflow tube rim is too low, water will be leaking into it before the fill valve reaches a shutoff level.

I would remove the lid, do a simple flush and see how the fill valve and overflow interacts. There should be an adjustment screw to tweak the water level lower or higher. Play with that. If all else fail, replace the fill valve yourself or use a different plumber.



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