3 Potential Causes Of Low Water Pressure In Your Toilet

Posted on: 25 June 2015


When you flush a toilet, the outgoing water leaves through the drain and fresh refilling water comes in from the tank. Sometimes problems with the toilet or your home's water supply can lessen the amount of water that reaches the bowl during a refill. This can impede the flushing function of your toilet and increase the risk of staining.

There are a few potential causes of low water pressure in your toilet. Two are problems you can fix if you can purchase some plumbing supplies and read directions. But another cause should be left in the capable hands of a professional plumber.

Shut-Off Valve Issue

The water enters the tank by traveling up a pipe that's connected at one end to your home's main water supply and at the other end to the fill valve inside the tank. Between those ends is a shut-off valve that you can turn off quickly if the toilet started to overflow.

Sometimes the shut-off valve can get bumped so that it's partially turned off. This position means that some water can still get through to partly fill the tank but the overall water pressure is a lot less than normal. Most shut-off valves need to be turned counterclockwise until it won't turn anymore in order to be fully open.

If the shut-off valve seems damaged, that could also be causing your water pressure problem. Leave that fix up to a qualified plumber so that you don't end up with a flooded bathroom.

Fill Valve Issue

Is your shut-off valve healthy and open and you still don't have enough water? The fill valve could be broken and there are a few different parts that could cause low water pressure.

First, the tube at the bottom of the fill valve could be somehow blocked and stop the water from coming into the tank. You can figure out if this is the problem simply by looking in the tank. If water isn't even coming into the tank and the shut-off valve is fine, then you will need to replace the entire fill valve assembly.

What if your tank is getting water, but the level isn't going high enough? There's a mechanism at the top of the fill valve assembly that tells the assembly when the water is high enough. This mechanism often looks like a floating plastic balloon. A malfunctioning floater can cause the valve to think the tank is full well before it actually is and your water pressure will be low. Replace the floater, which is available to purchase separately, but replace the entire assembly if that first replacement doesn't work.

Central Plumbing Issue

Checked all the water-controlling parts of the toilet and something's still not right with your water pressure? You could have a clog down the line that's preventing enough water from coming up through the pipes and into the tank.

There's no easy way to check this for yourself. Once you've ruled out the common problems with the actual toilet, call a plumber (such as one from C B Lucas Heating & Air Conditioning) for a pipe diagnosis.