Low Water Pressure In The Bathroom Sink? Fix-It With These Steps

If you’re experiencing low pressure in your bathroom sink, it can be seriously frustrating. Don't despair, though, because help is at hand. Here are some common reasons why the water pressure might be low in your bathroom sink and how you can fix it yourself. First, it's important to know how bathroom sinks work so you can familiarize yourself with their structure and make understanding how to fix them more clear. 

How Bathroom Sink Plumbing Works

Your bathroom sink plumbing is divided into two parts — the first part is the supply, which handles the delivery of fresh water to your bathroom sink. The second part is the drain, which removes water once it has been used.

Water is delivered, generally under high pressure, to your sink from the main water supply. It enters tubes that carry hot and cold water to the faucet. Before the water enters your home's plumbing, it will pass through a shut-off valve.

Then the water supply plumbing feeds into the bathroom faucet fitting, where a flow restrictor disk and aerator regulate the flow of water. These components can also be potential trouble spots for your bathroom sink water pressure.

Once the water passes through the faucet, it enters the basin of your sink and exits the basin through the drain, entering a J curved pipe known as a sink trap. The shape of this pipe prevents unpleasant odors from backing up into your bathroom and prevents unwanted items from clogging the pipes down the line. The water passes through the sink trap and into your wastewater system.

When dealing with low water pressure, it’s better to look at the former section of your sink plumbing — the delivery of fresh water.

4 Causes & Fixes For Low Water Pressure In A Bathroom Sink

Now that you have a better understanding of how your bathroom sink plumbing works, here are some of the common reasons for low pressure in a bathroom faucet. Plus, some of the fixes you can try to get your bathroom sink functioning properly.

Valves Are Closed

One of the simplest and most common causes of low pressure in your bathroom sink is the shut-off valves. Your home will have a shut-off valve that controls the flow of water into the property. Closing this valve will stop water flow, so that maintenance or replacement can be done without making a mess.

But this is not the only shut-off valve at your property. Your bathroom may also have shut-off valves that handle the flow of water in this specific part of the house. If these valves are closed, no water will flow to the bathroom sink. If the valves are only partially open — for instance, if you have recently had work done at your property and the valves were not fully opened upon completion — this can result in low pressure.

How to fix it:

Make sure both the master valve and the bathroom shut-off valve are set to the open position. In the event that pressure remains low, make sure the valves are fully open and check the water again. A licensed plumber can help if you’re having any trouble finding or opening the valves.

Flow Restrictor Is Not Operating Properly

The bathroom sink faucet is fitted with a flow restrictor that controls the flow of water through the fixture. This is a small plastic disc that is placed within the faucet to narrow the opening. Water flow is permitted only through a small hole in the center of the flow restrictor.

If this flow restrictor is not operating as it should or operating too well in restricting the flow, you may experience low pressure whenever you use the sink. This can also completely prevent water from coming out. There are a number of possible causes for this, like the restrictor hole being too small or it might have become clogged or blocked.

How To Fix This:

You need to dismantle the faucet to remove the flow restrictor disc and examine it. If the hole is too small, you may need to replace the disk. If the hole is simply blocked, you might just need to give the restrictor disk a good cleaning before reassembling the faucet.

Blockage In The Water System

Your home's water supply depends on adequate pressure for between 45 and 80 psi (pounds per square inch) to get through your home's pipework. So, if there is a blockage in the pipes, this is a prime culprit for a loss of pressure. 

How do blockages occur in your pipes? Most develop over a long period of time. A common cause is mineral deposits that build up on the inside of the pipework. They can also occur when debris from construction work is left behind in the pipework, restricting the flow of water. 

In many cases, this will cause a reduction in water pressure around the home. It won't be isolated in one specific location. However, if the blockage occurs in your bathroom or in the pipework leading to the sink, it may cause the sink alone to lose pressure.

How To Fix This:

Flushing, cleaning, and repairing the water pipelines should remove any blockages. In the case of older pipework — or when the pipes have become damaged over time — system components may need to be replaced. A licensed plumber can help you diagnose the problem and address it.

Water Aerator Is Blocked

Blockages can occur elsewhere in the water system. One of the prime locations for blockages that affect the pressure of your bathroom sink is in the water aerator. The water aerator is a component of the bathroom sink faucet and works in a similar way to the flow restrictor, regulating the flow of water through the faucet nozzle. As the aerator is located at the very end of the nozzle, you will be able to see it without dismantling the faucet.

The aerator itself is made of a fine wire mesh. It maintains a consistent water flow and also provides some filtration to the water as it passes through. If there are any contaminants in the water, these may become trapped in the mesh. This can disrupt the flow of the water, and it can cause you to lose pressure in your sink faucet.

How To Fix This:

You may be able to see if the aerator is blocked without dismantling the faucet. However, to be sure, you will need to take the fitting apart. Cleaning the aerator should hopefully fix the problem, but you may need to replace the aerator if there is any damage or corrosion. Most hardware stores will carry universal aerators you can use to replace it.

Low water pressure, whether its in your shower head or bathroom sink, is an annoyance you don't want to deal with. There are a number of reasons why a bathroom sink and faucet water pressure might be running low. They also have one thing in common — they’re all fixable. In most cases, you can fix low water pressure by yourself. However, when necessary hiring a licensed professional plumber to help you discover the problem and deal with it is the best way to go.

About the author 

Glen Wojcik is the owner of Pioneer Valley Environmental of Ware, MA. With over 20 years of experience Glen, a licensed plumber and HVAC contractor, puts his team in the right place to serve home and business owners throughout Massachusetts.