Q: In one of our bathrooms (built in the 1960s), the water pressure in the shower is low. I’ve changed showerheads and it makes no noticeable difference. This seems strange because it is located next to the master bathroom (remodeled in the 1990s), which has great water pressure. While both bathrooms must be connected to the same main water pipe, the showers have remarkably different water pressures.
I’m planning to renovate the old bathroom, taking out the old tiles and putting in new ones. This will give me access to the shower pipes, so is it an opportunity to fix the water pressure problem, and if so, how?
A: You’ve provided all the clues we need to solve the problem. The 1960s shower has low pressure, while the newer model has great pressure. You’ve changed the showerhead and that didn’t help. So we can rule that out.
Yes, they are connected to the same main line, so the problem has to be in the shower itself.
We’re pretty certain that the low pressure you’re experiencing in the 1960s vintage shower is caused by a blockage in the valve that regulates the water flow. After all, the poor thing is more than 40 years old and has a right to be a little tired.
Tub and shower supply valves of that era came with rubber washers. These washers probably haven’t been changed in years, if not decades. We’d bet there is some debris stuck in the valve. We’d also bet that the debris is actually pieces of a worn-out rubber washer.
The solution is to replace the washers in the shower supply valve.
Start by turning off the water at the main shutoff valve to the house. In climates that don’t freeze, the shutoff valve is usually located where the water main lateral enters the house.
Next, pry the cover from the faucet handle and remove it from the cold water supply. Handles are usually attached to the valve stem with a Phillips-head screw. Next unscrew the escutcheon that covers the hole where the valve stem penetrates the wall.
Unscrew the nut holding the stem in the valve and unscrew the valve stem out of the valve. At the end of the valve stem, there should be a rubber washer held in place by another small Phillips-head screw. You may not be able to recognize it because of deformity, and pieces of it may be missing. Inspect the housing for debris and remove anything you see.
Take the valve stem to the local hardware store and get some replacement washers. Install a new washer on the stem and reverse the steps you just took to put the valve back together. Repeat the process with the hot water valve.
Once you’ve replaced both washers, turn on the water and test the installation. Remove the showerhead so any debris left in the valve will have an unobstructed path out of the system. This should do the trick.
In your future bathroom remodel, we definitely suggest you replace the old shower valve. It’s the same principle as replacing a thermostat in a car when the water pump goes. If the area is open, replace the old part. If you don’t, sure as shootin’ you’ll be tearing into the new shower to fix the valve you should have replaced as part of the remodel.