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Causes of Low Water Pressure in Kitchen Sink

low water pressure in a kitchen sink

If you begin noticing that the water coming out of your kitchen faucet doesn’t have as much pressure as it should, the first thing to check is whether it’s a whole-house issue. Are all the taps affected, or only the kitchen sink? If the kitchen is the only tap with low pressure, it’s time to consider the potential causes of low water pressure in a kitchen sink so you can determine what might be causing it, and fix it.

The most common causes of low water pressure in a kitchen sink are a clogged aerator or a clogged cartridge. The aerator is the part of the faucet that is at the very end of the spout; it is the last thing the water touches before it comes out into the sink. Most aerators become clogged over time due to mineral deposits in hard water. Fortunately, they are simple to clean when they become clogged. Simply unscrew the aerator, remove the metal or plastic screen inside and clean it with a toothbrush.

To get the aerator extra clean, you can soak it in vinegar overnight and then rinse it off the next day before reattaching it to the end of the faucet. In most cases, that should clear the clog and improve the water pressure. It’s also a good idea, every few months, to tie a gallon bag of white vinegar over the end of the faucet overnight. This should help to prevent future clogs in the aerator and extend the life of your faucet over time.

If you cleaned the aerator and the water pressure is still low, the next thing to check is the cartridge, which is located within the handle. (Note that if you have a kitchen faucet with two handles, one for hot water and one for cold, you don’t have a cartridge faucet; instead, you have a compression faucet.) A quick way to check whether the cartridge is clogged is to run the water while the aerator is off the faucet. If the water pressure is still low, the cartridge may be the culprit. In order to check it, depending on what style of faucet you have, you’ll need to pop the top off the handle or remove it altogether by removing the set screw located in the bottom of the handle.

Once you have taken the handle off, you’ll unscrew the ring-shaped cartridge cover inside. This will allow you to remove the cartridge itself and inspect it. The cartridge is cylinder-shaped and usually made of brass or plastic. If there’s a lot of debris inside, it’s time to replace the cartridge; newer cartridges with only minor debris can often be cleaned. You should also inspect the rubber O-ring seals to make sure they haven’t deteriorated. If they have, you can purchase a repair kit from a hardware store that contains these O-rings along with a replacement cartridge.

If both the aerator and the cartridge are in good shape but the water pressure is still low, the next item to check is the supply line. You’ll need to shut off the water under the sink before disconnecting one of the supply lines and dumping out the water inside into a bucket. Next, keep the line pointed into the bucket and turn the water back on. If water comes out, then the problem causing the low water pressure is likely within the faucet itself. In this case, it’s not worth trying to repair the faucet; it’s better just to replace it with a new one.

If no water comes out of the supply line, it’s time to call a reputable plumber who can provide you with an accurate diagnosis of the problem, and use their tools and expertise to resolve the plumbing problem.

It’s also important to note that if you notice low water pressure only when the hot water is running, it’s less likely to be due to a clogged aerator and more likely to be caused by sediment in the home’s water heater. A licensed plumber can flush the water heater to improve the issue. Regular flushing of the water heater (every six months, or more often if your home has very hard water) is a good idea in general, as it extends the life of the water heater, reduces energy use and gas or electric bills and keeps your hot showers nice and hot instead of lukewarm.

As we previously mentioned, if you’re experiencing low water pressure in your kitchen sink (or any other faucet in the house), one of the first things to check is whether the aerator is clogged. But many homeowners don’t understand the role of a faucet aerator.

a sink that has been equipped with a faucet aerator

What Is a Faucet Aerator?

If you’ve ever noticed that the very end of the faucet—the part where the water comes out—is able to be unscrewed, you’ve also probably noticed that there is a small, round, mesh screen inside the metal part that unscrews. This mesh screen is the faucet aerator; it is made either of plastic or of metal, and it has several purposes.

The aerator’s primary function is to mix air with the water rushing out of the faucet in order to reduce the water flow and also reduce splashing. If you unscrew the end of the faucet and turn on the water, you’ll see just how much more force water flows out of the faucet into the sink when the aerator is not present. What the aerator does is to break the single, solid stream of water rushing through your home’s water pipes and faucet into several tiny streams. This conserves both water and energy, and in the end, the result is that the person using the faucet feels like the water pressure remains high.

Sediment and debris can build up behind the aerator over time, leading to clogs that reduce the water pressure. This is especially true in homes with hard water. Calcium deposits in hard water can further clog an aerator. If your home has particularly hard water, it may be worth considering the pros and cons of purchasing a water softener.

When the water pressure is low, the first thing to do to try to resolve it is to clean out the aerator. As we mentioned earlier, it’s also a good idea to soak every faucet in your home in white vinegar every few months, by filling a gallon bag with vinegar and tying it onto the faucet with the faucet’s end submerged. Again, this is especially helpful in hard-water homes. Along with preventing clogs, periodic vinegar soaks will extend the life of your faucet over time.

In some older homes with original fixtures, the faucets in the home are not equipped with aerators. In this case, it’s a good idea to have a professional plumber install aerators on the faucets in order to reduce water flow and splashing and save on water usage and energy.

Sometimes people notice the water pressure is low, but only when the hot water is running. In that case, there could be a totally different problem.

a sink where the Hot Water is Pressure Low but Cold Fine

What if My Hot Water Pressure Is Low but Cold Is Fine?

If you have a sink in your home where the hot water pressure is low but cold is fine, it can indicate an issue with your water heater. Typically, if your hot water heater is having issues that cause low water pressure when the hot water is running, it won’t affect only one faucet in the house. Rather, it will affect every faucet in the house when the hot water is turned on.

Just as with faucet aerators, water heaters build up sediment over time if they aren’t flushed regularly. Tank and tankless water heaters should be flushed annually, or even more often if the water is very hard. Calcium and other types of sediment in the water build up over time, and if they aren’t flushed out, they can reduce the water heater’s capacity to heat water, increase its energy usage and lower the hot water pressure throughout the house. If you’re running out of hot water faster than before and your hot water pressure is low, it’s probably time to get your water heater flushed.

If your water heater has sediment buildup that is causing low hot water pressure in your sinks, a licensed plumber can flush the water heater to resolve the problem. If it hasn’t been flushed in five years or more, however, flushing may not work. There may be too much sediment and debris built up inside the water heater for flushing to be effective. If you can hear popping sounds coming from your water heater, this is a sign that there is so much sediment buildup inside that it’s too late to flush, and the water heater will likely need to be replaced.

This is why it’s a smart idea to contact a plumbing professional to perform routine maintenance on your water heater in order to avoid plumbing problems that would otherwise occur. Regular water heater maintenance will extend the life of your water heater, reduce energy use along with your gas or electric bills and keep your hot water flowing well.

ABC Can Resolve Water Pressure Problems

Trying to fix problems with your water pressure can take a lot of trial and error. Instead of spending your precious free time trying to diagnose the problem, contact ABC Home & Commercial Services. Our licensed plumbers will be able to quickly locate the problem and then get to work on resolving your plumbing issue. Also, if your area has hard water, you can rely on us for honest advice on what size water softener would be best for your home.

Tom Riggs

Tom Riggs is the Division Manager for Mechanical Services, overseeing sales and operations for HVAC, Plumbing, Electrical, Appliance Repair and Water Quality for all ABC Austin branches. He joined ABC in 2014. Before ABC, he was an HVAC Service Technician, HVAC Comfort Advisor/Sales and Operations Manager. Tom attended Universal Technical Institute. He's an avid outdoorsman and enjoys country living with his wife and two sons.

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