Low Hot Water Pressure

Low hot water pressure is usually caused by sediment, rust, calcium deposits or other debris in the plumbing lines or faucets.

This often occurs after the plumbing has been worked on, water heater replaced etc.

Sometimes the pressure will slowly decrease over a period of time, particularly if your home has been plumbed with galvanized pipe.

If you have just moved into a house with low hot water pressure take a look at the plumbing going into and out of the water heater. If it has been plumbed with 1/2 in. pipe going in or coming out you will not get as much pressure as you could if it were plumbed properly.

Corrosion and rust will slowly clog galvanized pipe. There's not much you can do about this except replace the pipe, however it is worthwhile to check your aerators and faucets. Just follow the guide below.

Low water pressure in part of the house
Sink faucets

Clogged Aerator on kitchen sink faucet

A clogged aerator is the most likely cause of low water pressure in a sink faucet.

Remove the aerator with a pair of pliers (see pic).

Cut you hot water on with the aerator removed to see if you have more pressure. 

To clean your aerator.
Tap it on the counter top and the inside parts will come out.

Give it a good cleaning, put it back together and reinstall it.

Now check the hot water pressure. If cleaning the aerator didn't help go to the next step.

Faucet stem clogged, remove handle

You may have a clog in the faucet itself. This is an easy fix.

Turn the hot water off under the sink. Use a knife to pry up the ID button on the hot side faucet handle.
Remove the screw holding the handle. Pull up to remove the handle.

Remove stem retainer nut

Unscrew the stem retainer nut and pull straight up on the stem, it should pop out.

The stem may have a washer mounted on the bottom of it. If not there will be a washer and spring inside the faucet housing.

Gently remove the washer and spring with a small screwdriver.

Remove stem, flush debris ftom faucet

While holding a cup or glass over the faucet turn the hot water supply on and off several times.
This should flush out any debris stuck in the line. Check and clean the stem.

Reassemble the faucet and turn the water on and check the pressure.

If you still have low hot water pressure the problem may be the supply line under the sink.
Remove the line from the shut-off valve and the bottom of the faucet and clean or replace it. Also check the pressure coming out of the shut-off while you have the supply line off.

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Single handle faucet

Turn both the hot and cold water off under the sink.
Remove the handle.
Loosen and remove the retaining collar.
Pull the ball cartridge out.
Remove both washers and springs from the faucet.

Place a glass or cup over the faucet and turn the hot water on and off
several times. Its a good idea to flush the cold side while the faucet is apart.

Reassemble the faucet and turn the water on.

Low pressure in the bathtub and shower

If you have low hot water pressure in the shower only and not in the tub remove the shower head with a pair of pliers.
Look into the back side of the shower head.Pry out any parts you see with a small screwdriver and clean everything.

If you have low pressure in the tub faucet it will disassemble much the same way as the other faucets.
If you have a two handle tub faucet you can cut the hot water off at the water heater. Only remove the hot side stem.

On a single handle faucet you'll find a screw on each side of the faucet body after the large chrome cover is removed. Screw both of these in tight before you remove the stem. If you can't see them (sometimes builders cover these up) you need to cut off the main water supply to the house.

When you have everything removed from the faucet turn the water on and off several times to flush out all debris.
Reassemble the faucet and give it a try. Don't forget to clean the shower head if you haven't already.

Low water pressure in the clothes washer

The water inlet valve on the back of your washing machine where the water hose is attached, has a screen to catch debris before it enters the machine.

Cut the water off behind the washer. Remove the hot side hose. Carefully pry the screen out with a small screwdriver. Clean the screen and reinstall.
Some washing machine hoses have screens in them also.

Whole house low hot water pressure

To solve this problem we'll have to start at the water heater and eliminate possible causes one at a time.
Water can only come out of a water heater as strong as it comes in. If you have a 3/4 in. copper or cpvc pipe bring water into the water heater and 3/4 in. leaving the water heater and your cold water pressure is strong you should have good hot water heater pressure.

If you have older galvanized pipe or any 1/2 in. pipe entering or leaving the water heater you will not be able to get great hot water heater pressure.

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