Low water pressure in your bathroom sink can be a huge pain. Luckily the solution is usually pretty easy to trace and can be fixed by most homeowners. Here are the causes of frustratingly low water pressure in your sink and how to fix them.
First source the low-pressure problem
Before we begin it’s important to determine if there is a lack of water pressure in your whole house or if a limited water flow is isolated to your bathroom sink. To see if there are low water flow issues in the rest of the house, go and turn on other faucets one at a time in different rooms to see if the water pressure is the same as it’s always been or if the flow of water is slowing down.
If the rest of the house has comfortable water pressure, you know it’s a bathroom faucet sink-specific issue. The next thing to do is determine if the water pressure is low all the time or sporadically.
Next, determine if it’s a temporary issue.
The reason for checking this is because water can be used in other parts of the house at the same time. When that happens, it can cause a decrease in water pressure.
For example, if your whole family gets up at the same time, you could have multiple faucets running all at once, not to mention showers and toilets flushing as well.
All these fixtures running together can be the reason for weak water pressure in your house. But if you are just using your bathroom sink, you may think that it’s specific to that one spot, when in fact, it’s just a timing issue.
Assuming you have checked these two things and still have low pressure in your sink, it’s time to get to the specifics.
Next, check hot and cold water pressure separately
We want to see if the bathroom faucet’s water pressure is conditional on the cold water faucet or the hot water faucet. It could be that there is a water pressure issue with just the hot water or just the cold water line.
Test each of them to see if the water pressure is the same. You do this by turning on each bathroom sink faucet water to full one at a time, and checking if there is a reduction in water flow and then turning it off.
If you find that the hot water pressure is weak, but the cold water pressure is strong you know that there is a hot water issue, narrowing down your issue. At that point, it may be a low hot water pressure issue or a water heater leak issue.
The more you can narrow down the source of the low pressure in your pipes, the easier it will be to fix it.
Check the cold and hot water shut-off valves are fully opened
If you have recently replaced your taps, you will want to check both the cold water valves and the hot water valves are fully open. This is often the culprit for bathroom sink water pressure issues.
These knobs are in the sink cabinet and can get bumped and end up partially closing. Inspect the cold water and hot water shut-off valves to see if they are fully open. To see if they are fully open, turn them completely until you know the water flow is open.
Check the Faucet Water Aerator
The first thing you can check once you know the shut off valve is fully open is the bathroom sink faucet water aerator. The water aerator on a bathroom sink is made of metal or plastic and is a mesh that is designed to aerate the water, giving it a better flow, and is located on the end of the faucet. It also filters any dirt or other things in your pipes making their way to your sink.
Because the water aerator serves as a filter, it can become plugged over time. Take a look at the aerator and see if the mesh is plugged at all. Any blockage in this will significantly cut down the water pressure in your bathroom sink. This is often the source of many low water pressure issues.
How to fix the water aerator
To fix this low water pressure issue, remove the aerator from the end of the bathroom faucet by unscrewing it. Usually, you can do this by hand, but if the build-up is old, you may need a wrench. Never use pliers as they can bend the plumbing fittings. If you need to understand the parts of a faucet aerator, see the image.
Inspect the aerator to see if there is an issue with the holes. If the aerator’s holes are plugged from mineral deposits, you can scrub it with a cleaning toothbrush while running it under water. Alternatively, you can try to clear out the holes with a safety pin as well if you prefer.
If there is excessive hard water buildup, you can put the wire mesh in a vinegar and water solution overnight. Leaving it in vinegar overnight will help break down the mineral build-up and remove any of the hard water buildups that have occurred. Once you have done that, rinse it in the morning and put it back into place.
Check the water flow restrictor.
What is a water flow restrictor?
Before you can check the flow restrictor, you need to know what that is. A flow restrictor is a small plastic disc inserted into the tap just before the faucet aerator. It has a hole or many holes in it, and it regulates the flow of water from the tap by restricting how much water can come through at any given time.
How to check the water flow restrictor disk
Remove the clogged aerator and inspect the plastic disk known as the flow restrictor. Check the flow restrictor to see if there is a big enough hole for the water to be coming through and make sure there are no clogged holes. If there is any build-up on the restrictor, you can clean it.
Over time mineral deposits from your water can build up on the aerator and begin to clog the holes. As this happens, your water pressure will become less and less.
How to fix the water flow restrictor disk
The easiest way to fix the low flow restrictor issue is to remove the clogged aerator piece at the end of the faucet. Usually, you can unscrew this with your hand, but depending on the faucet you may need a wrench.
Remove the plastic disk inside the aerator and clear the holes using a safety pin. You can also widen the holes using a screwdriver or a sharp knife if you believe that is the issue.
Alternatively, if there is some buildup on the flow restrictor, you can remove the mineral buildup by soaking it in vinegar overnight and putting it back in place in the morning.
The question that often comes up is, “Should I remove the flow restrictor disc completely?”
While this is an easy way to increase water flow, it can also significantly increase the water usage of a faucet and end up costing you money. When it all possible, it is best to slightly widen the holes or remove the build-up, as we previously mentioned.
Clogged Water Supply Lines
If none of the above have worked to improve your low water pressure, you may have a plugged water supply line. This happened to us when we built our house, there was a bit of dirt and debris in the water lines, and it needed to be flushed out. Apparently, it’s pretty common in new places.
It’s a fairly simple thing to fix but sounds a lot more complicated. So let’s break down what you need to do to flush your water supply line and restore water pressure.
Here’s how to flush your water lines
Step 1: Turn off the shut off valves
First, turn off the shut-off valves located under your bathroom sink. Turn them both clockwise until they are completely turned off. You can also turn off the water at the main shut off valve, but that turns off water to the whole house.
Step 2: Check the water is off and drain the lines
Next, turn on the hot and cold faucets. We do this to remove any water that is still in the line after the water drains out of the lines. Once they have been drained, turn the faucets off again.
Step 3: Remove the water line from the faucet
Next, you will want to remove the water supply line from the faucet. Use a wrench and remove the water lines from underneath your faucet in the sink cabinet. These can be in a hard-to-reach area, and you may need a different type of wrench to do this.
Step 4: Flush the lines.
Get a bucket and put your water supply valves into the bucket. Next, turn on the water shut-off valves. The water will start to come out of the supply lines and into the bucket. Let the water flow for about 30 seconds. This should remove anything in the plugged water supply lines.
Step 5: Reattach the water lines to the faucet
Turn off the shut-off valves again and reconnect the water lines back onto the faucet.
You will want to make sure you tighten them with a wrench; they don’t need to be super tight (like we did when replacing the water supply line). Lastly, reopen the shut-off valves and turn on your faucets to see if the water pressure has improved. If you opted to turn off the main shut off valve, instead turn it back on too.
Check underneath your sink to make sure everything is connected properly and not leaking. A great way to make sure you detect any leaks is to use a wifi water sensor, we have one, and it’s caught several leaks for us in the past year.
Turn on the water and see if your water pressure has improved.
Check for leaks
Another reason for low water pressure is that there is a leak somewhere. Over time water will wear down parts of your plumbing, and it could be that you have a leak somewhere. Inspect your bathroom fixtures to see if there are any leaks under the countertop.
Lastly, Call a Plumber
If you try all of these low water pressure fixes in your bathroom sink and nothing works, it could be something larger. At this point, you should contact a professional plumber. You have done everything you can, and by calling in a professional, they can assess the issue and fix it quickly.
Looking for more repairs and maintenance? Read this:
- 10 Boiler problems to check before calling a repair company
- How to turn off the water to the toilet (before it’s too late)
- How to improve your flushing power
- What to do when your toilet keeps running.