What Causes Low Water Pressure in Only One Faucet and the Entire House?

An insufficient flow of water coming out of your tap is usually because of a blockage but there could be other reasons why the water pressure is low. You will need to diagnose what causes low water pressure in only one faucet. If the whole house has low pressure then you need to investigate this too. In this guide, we are looking at both of these things.

When there is only one fixture that has low water pressure then you can apply these remedies to that faucet or the pipes that serve. Wider spread water pressure issues could be an indication of plumbing system problems. If you can notice low water pressure around the home or only the kitchen sink faucets, the first thing to do is narrow down what’s causing it.

1 – Water Meter Valve

For most homes, there are two shutoff valves that control the hot and cold water that flows into your home. The first is the water meter valve which will be next to the water meter where the main city supply line enters your home. Normally this is a valve that you don’t need to use as it belongs to the water company and is used by their personnel.

However, if you’re noticing low water pressure in your home or in a faucet, especially if work has recently been done on your plumbing, it’s possible that the valve isn’t fully open. The water pressure in your home being low could be due to a repair recently being done. Make sure to check the meter valves which you can find in home. It could be on the outside wall, in an underground box or in your utility room. Basements and garages may also be places where a water meter could be.

You will know that a valve is open fully by the handle. It should be completely parallel with the water pipe. If the handle is at an angle then the valve isn’t fully open which will affect your water flow.

2 – Shutoff Valve

Another main shut off valve in the home is usually found inside your house. It will be where the main supply comes through to your home through the foundation wall. Once again you need to make sure the valve is completely open. A gate valve should be turned fully counterclockwise. A ball valve will have a lever handle and this has to be parallel to the pipe if it is fully open.

Much the same as the water meter valve, the main shut off valve can be left partially open after a repair has been done on the system. Anything from hot water heater repairs can lead to a change in the water pressure. Think about any recent repairs you’ve had and in the low pressure in the house or in the tap has happened after this. If this is the case, there’s a good chance the valve wasn’t opened up again once the repair was done.

3 – Failing Pressure Regulator

A fault in your water pressure regulator or the pressure reducing valve could be causing a lower flow rate of water into your home. A pressure regulator is another control valve that reduces how much pressure is put into your plumbing system. It keeps it at a safe level so that your pipes don’t become damaged. Not every home has one, but if yours does and it’s faulty it can mean the pressure is low or it spikes.

A failing pressure regulator will have an effect on all faucets and fixtures around the home and it happens pretty quickly. You may be able to replace the regulator by yourself with the right brand and size but in most cases, it’s better to call in a plumber. Replacing this part means you have to shut off the water supply to your home with the shut off valve.

If you want to test just how low your water pressure is then you can attach a gauge to your outdoor hose or to the pressure regulator. The recommended amount of water pressure is around 75 pounds per square inch depending on the area you live in. Pressure that is testing low could indicate that you need a new pressure regulator.

4 – Old Pipes

Easily the most serious (and most expensive) reason for having low water pressure in a faucet or throughout your home is the pipes. Old galvanized steel pipes can be corroded over time which then restricts the flow of water significantly. The pipes corrode from the inside out and the build-up of this corrosion will gradually shut the pipe off from the water flow.

Because this is a developing problem that happens gradually over years the reduction in pressure will be steady. It won’t be a sudden noticeable drop in the pressure. However, if you own a home with old pipes that were already corroded then the problem can worsen quite quickly.

The only solution for you in this situation is to replace all of the old metal pipes with new ones made out of plastic or copper. This can be very costly as you will have to replumb your entire home.

5 – Faulty Fixtures

A water pressure problem that is affecting one sole faucet could be a simple problem with that fixture. Low pressure in a specific area like this could usually be down to clogging or corrosion which then causes slow water flow.

Another issue with faulty fixtures is if the seals and connections have gone wrong. You need to inspect the faucet to see if there is anything around it that could be causing low pressure for your water flow. Hard water that flows through a fixture regularly can cause a buildup of minerals so it’s important to make sure your faucets are descaled regularly.

6 – Faucet Aerators

All faucets around your home with have an aerator attached to it right at the tip. This is the part that stops the water from splashing everywhere and making a mess for you to clean up. It’s not an uncommon occurrence to get a clogged aerator over time which will then reduce your pressure from a single faucet. Kitchen sink aerators are very easy to remove and then you can clean them to reinstate the right flow for your water supply.

7 – Faucet Cartridge or Stem

The cartridge or stem for a kitchen faucet is the part that connects to the handle so that you can control the hot or cold water supply. If this has become broken or faulty over time then it will need to be replaced. This is a job for those of you who are handy but may be a bit of a stretch for those who aren’t, in which case you’ll need a plumber.

Something to keep in mind is that if you have newer faucets then the aerators and cartridges are designed to be low flow devices. This means they put out less water and it could be different from the kitchen faucet you had previously. Small problems that occur with a faucet cartridge or stem can result in noticeable drops in the pressure.

8 – Water Supply

Our last reason for the drop in water pressure could be because of problems with your municipal water supply. A plumbing professional will help you out in this situation as they can measure the water pressure as it enters your home. If it’s low then you need to reach out to your water supplier so that they can fix the issue.


We hope that you could find the cause of your low water pressure problems either in a single faucet or throughout your home in our article. Remember to have a look at the rest of our website where we give you lots more guides on plumbing and faucet problems. If you enjoyed our guide then make sure to share it online.


Why is water barely coming out of my faucet?

The problem could be that your water valves are closed or that there is a clog in the system. The best place to check for water pressure problems is the aerator.

Can a bad faucet cause low water pressure?

Yes, a faulty faucet and fixtures can absolutely be a cause for low water pressure. It’s best to get a plumber in to have a look and make sure it’s the faucet or something more serious with your water system.

What is the most common cause of a weak water flow from a faucet?

Usually, if it’s just from one faucet the problem will be a faulty fixture or that it needs a cleaning. Over time calcium deposits and other bits of debris will build up in the faucet which can then lead to the water coming out slowly. Sometimes this can be easily fixed with a cleaning mixture of white vinegar and baking soda.

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