How to Fix In-Wall Hidden Tank Toilets

Most Americans are used to the standard floor-mount toilet, where the tank is immediately accessible. Wall-mount toilets connect to the drainpipe through the wall instead of the floor, and, often, the tank is installed in a frame behind the bathroom wall. Fortunately, troubleshooting problems is fairly straightforward once access is obtained.

The tank on an in-wall toilet is accessible through an access plate, normally located behind the flushing mechanism. Homeowners with this kind of toilet setup often panic when something goes wrong. However, once the access plate is removed, the toilet can be fixed just like any other.

In-wall toilets have the same types of problems that standard toilets do: water continuing to run after a flush, problems with the water level in the tank, leaks from bad connections and movement from an unlevel installation.

Most of these problems are easy to investigate, and you may not need to call in a plumber at all. First, you'll need to identify more about the problem and proceed from there with troubleshooting.

Perhaps you noticed that the water in your toilet is still running after a flush. This can happen when the flapper in the tank doesn't end up sitting flush to the opening, which produces a slow leak into the toilet bowl. The running water sound you hear is the tank refilling as the water drops below the fill level.

If this is happening, pull off the flush actuator cover to check the flush valve. You'll see a bar, connected to a rod or spindle that connects to the actual flush mechanism in the tank. Try adjusting the bar or rod by hand to make a better seal.

If this doesn't work, the rubber valve seal, which is a part of the flush mechanism, may have worn out, and you'll need to replace it. Depending on your setup, you may be able to access it yourself; if not, you'll have to open up the drywall to access the tank.

If the water level in your toilet's tank is too low, the toilet may have problems flushing out solid waste. If it's too high, you're wasting water with every flush. In this case, access the flush valve as detailed above; then find the plastic rod or spindle.

Rotate clockwise to raise the level of water in the tank and rotate counterclockwise to decrease the level of water in the tank. You can test this with a few flushes before resealing the flush actuator panel.

Unfortunately, there isn't much you can do from the outside if there are signs of water leakage inside the wall. You'll first want to turn off the water supply and clean up what you can to try and find the leak visually. Check the bolts fastening the toilet bowl to the wall. If these have loosened, it can cause leaks.

Next, check the water supply lines that feed the toilet bowl for damage or aging and replace the hoses as necessary. If this doesn't fix the issue, you may need to access the tank inside the wall or talk to a professional.

If the toilet bowl isn't level, it can strain the connections and cause leaks or wear and tear. To fix this, remove the bolt caps and loosen the bolts on the sides of the toilet bowl with a wrench.

Using a level, move the bowl around until it is even. Hold it in place while tightening the bolts with the wrench. This may require two people — one to level and hold the bowl and one to tighten the bolts.