Pro Handyman Blog

If you see signs of water damage at a wall, here is a test you can perform. You can’t see through a wall of course and so when you see bulging drywall on the opposite side of the wall, you have to make some assumptions. The damage could be from the shower valve leaking, or it may be from a maintenance issue, such as caulking or grout.

You can start to narrow the field with this test. Check first to see that the water meter is not moving, meaning that there is no water passing the meter. Then go to the shower and remove the showerhead and cap the shower arm with a ½ inch cap. Now turn the water on to the shower valve. No water will flow out of the shower because the cap is preventing it. However, now the shower riser and arm is pressurized. You can remove the escutcheon plate to see if any water is leaking or dripping (it’s a good idea to do this before you turn the water on and again after…it gives you an idea as to where the leak is). If water is leaking, then you have a leak somewhere between the valve and the shower arm. If there is no leak visible, then go back out to the water meter and see if it is moving.

If the water meter is not moving, it will confirm that the shower valve is not leaking. If the meter is moving, make absolutely sure that nobody just flushed a toilet, or that the icemaker is refilling, etc. If nobody is using any water and the meter is moving, you may have a leak where you can’t see it, which would warrant further investigation such as opening the wall.