Determine the cause of the low water pressure. Often times, low water pressure can be a result of poor plumbing within the house.
Verify that the pipes are the proper diameter. Most modern building codes require pipes to be no wider than 1/2 inch (1.27 cm). If your house predates modern standards, you may simply have outdated plumbing. This can be easily resolved by installing a pipe reduction apparatus, which is available at any plumbing company. Follow the manufacturer’s instructions to install it.
Examine the condition of the pipes themselves. Sometimes, rust or corrosion can clog the pipes. The only remedy is to replace the worn out pipe. Again, follow the manufacturer’s instructions to install it.
Proceed with the following steps if the problem is low water pressure in specific faucets. If the pipes are not the problem, you could have a clogged faucet aerator.
Unscrew the aerator with a pair of pliers, and tap it on the counter to jostle the innards loose. Clean all of the pieces thoroughly and then reinstall them.
Check the pressure again. If it is still too low, then you probably have a clogged faucet. – Plumbers Columbus Ohio
Unscrew the stem retainer nut and pull the stem straight up. You will either find a washer alone at the bottom of the stem, or a washer with a spring within the stem of the faucet. Use a screwdriver to remove the washer and/or spring.
Block the faucet with a cup and turn the water on and off a few times. This should flush out anything causing the clog.
If you have a single-handled unit, remove the handle by loosening and removing the retaining collar.
If the pressure is low in the tub faucet, disassemble that faucet in the same manner as described above. Block the faucet with a cup, as previously, to flush out the clog. – Drain Cleaning Company
When dealing with a single-handled tub faucet, you will encounter a screw on each side, under the large chrome piece. Assure that these are both fully tightened before removing the stem.
Remove the shower head if the pressure is low there. Remove any internal parts with a screwdriver, clean each piece, and re-install it.
Turn the water on and off to remove any clogs, and reassemble the faucet.
Proceed with the following steps if the water pressure still hasn’t improved. In rare instances, the problem may be due to a problem in the home’s water pressure regulator. Usually, the pressure regulator is located somewhere near where the plumbing meets the house. If this is the case, unfortunately, you’ll have to call a Columbus plumbing company to reset it.
If you’re equipped with a water pressure regulator within your home, you can most likely reset it yourself.
Loosen the retainer, or lock nut, on the stem. Increase the water pressure by turning the pressure adjustment stem clockwise. Most manufacturers’ pressure settings are 45-55 psi. Residential codes normally stipulate a limit of 50-70 psi. You won’t be able to raise it beyond that standard. – Columbus Plumber
Verify the change in the water pressure by hooking up a lawn sprinkler, where the varying water flow will be evident.
If this is still ineffective, internal seats or screens may need to be cleaned within the unit itself. Perform these tasks with care, and always follow the manufacturer’s instructions for maintenance.