Low Water Pressure When Using Two Faucets

Do you notice low water pressure or a sudden drop in water pressure when you use two faucets? It is an aggravating yet common problem in bathrooms, kitchens, and other areas where two faucets or sources pull water.

If you are having issues with water pressure in your faucets, use this troubleshooting guide to get to the bottom of your plumbing issues.

What Could Cause Low Water Pressure?

A number of things can trigger low water pressure. When the water pressure is struggling in a single faucet, and the issues are isolated to that one faucet, the problem is usually quick and easy to decipher. In situations where the water pressure drops after a few seconds with several taps running, the culprit could be several different things.

Pressure Reducing Valves

Issues with the pressure-reducing valve could be causing low water pressure. If the water pressure starts normal, then drops, the PRV valve could be causing the problem. They are commonly located in municipal systems or situations where the water pressure exceeds 80 pounds per square inch.

When the water pressure becomes too high, pipes and fixtures may sustain damage. If the PRV is the issue, try adjusting the valve to see if it affects the water pressure in your home. If it doesn’t have any effect, the entire unit may need to be replaced.

If your water comes from a private well, then the water to your home is pressurized through a pressure tank that maintains a specific range of pressure. In residential homes, the ideal water pressure should be between 45 and 55 pounds per square inch. However, it usually ranges between 45 and 80 psi.

Shut-Off Valve

Check the shut-off valve, both to the main water supply and to the two faucets. If the valve is even slightly closed, it may affect your water pressure, so check to ensure that it is completely opened. If you recently had work done on the plumbing in your home or have children who could have bumped the valve, the shut-off valve in a slightly off position could be the problem.

If your sink has shut-off valves for each cold and hot water, and you are experiencing low cold water pressure, the shut-off valve specific to the cold water could be slightly off.

Shut-Off Valve

The shut-off valves to the specific faucets may be beneath the sink itself. The main water supply shut-off valves may be near your furnace or water heater or within three to five feet of wherever the water main enters the home.

Trapped Air

When air is trapped in pipes, it can lead to fluctuation in the water pressure in your home. As the water moves through the pipes towards your faucet, it acts as a sort of valve, causing spluttering and water flow from the faucet in occasional bursts.

Air can enter pipes through damaged tank bladders, a failing pump, a leaking suction line, leaks in the pipeline, or gas buildup in the well water system.

Clogged Pipes

If the piping inside your house has become clogged for whatever reason, it could be causing a lack of water pressure from the taps in your home. The water flow becomes disrupted, thus reducing water pressure to specific areas in your home.

This problem requires a hands-on approach and will likely need a professional to handle it unless you are a skilled do-it-yourselfer.

Corroded Plumbing

Over time, the plumbing in homes can become corroded, causing issues across the board. If the corrosion gets bad enough, leaks, water pressure drops, and other problems may occur. Replacing all of the plumbing in your home is a massive undertaking and will be an expensive venture, but it is worth the effort.

Older homes tend to have corrosion in the plumbing, as most piping have lifespans between 20 and 100 years. Galvanized steel pipes typically last between 20 and 50 years, while copper, brass, and iron materials may last from 40 to 100 years.

Corroded plumbing may cause low water pressure to the interior of your home but also to your outdoor faucets. Corroded or leaking pipes may impact garden hose spigots, outdoor faucets, and the like.

Broken Water Line

A broken or pinched water line also may be the culprit. Broken or pinched water lines usually cause issues across your home and typically aren’t isolated to two faucets.

Can A Bad Faucet Cause Low Water Pressure?

A faulty faucet can cause low water pressure. Bad parts within the faucet, such as a clogged aerator or clogged cartridge, can cause a sudden loss in water pressure.

One bad faucet may cause fluctuation in water pressure between two taps in the same room. For troubleshooting situations where the water pressure is low in two faucets in the same room, start by checking the faucets themselves.

Can A Bad Faucet Cause Low Water Pressure

How Do I Fix It?

If you can determine which of the two seems to experience low pressure, start with that one. Turn off the water supply to the faucet before taking it apart. Remove the end of the faucet and examine your aerator, which is the piece that sits inside the spout.

Verify that it is clean and there isn’t any mineral buildup or other debris. If there is gunk in the aerator, soak it in a water and vinegar solution. However, if the solution does not work to loosen the debris, you may need to purchase a replacement part.

Before replacing the aerator, turn on the water supply and check the water flow to the faucet. If the faucet is still experiencing low flow, then the low water pressure is likely not due to that specific faucet and is probably a widespread problem.

Can A Mixing Valve Reduce Water Pressure?

Some types of shower valves have what is called a thermostatic mixing valve, which separates control for water temperature and pressure. A malfunctioning mixing valve could potentially cause reduced water pressure. 

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