Why Would Water Pressure be Low in Just One Faucet?

We’ve written about water pressure in several past blog posts, including troubleshooting, likely causes, and how to resolve low-pressure experiences throughout your house.  For instance, we know that if low water pressure is house-wide, the likely cause has something to do with your pipes or your water supply.

Water Pressure Troubleshooting

If the water pressure is low throughout, the first question likely to occur to you is to ask if there is a water pressure problem in your area.  Perhaps hydrants are being flushed, or maybe there has been a break in a water main.  Neighbors will be a good source of information to answer this question.

Secondly, you’ll want to check the water shut-off valve in your basement where your water supply comes into your home.  Perhaps the valve is leaking.  While valves will last a long time, they are not eternal. 

There may be debris in your pipes, the sources of which are several.  That is not the purpose of this piece, though.  We simply want to consider water pressure troubleshooting, generally.

But what if the low water pressure is localized to just one faucet or on one side of a faucet? Is it possible that low water pressure would be isolated to only one faucet, such as in your kitchen?

Low Water Pressure in Kitchen Sink Only

Faucet Dripping

If the low water pressure is limited to a single faucet at your kitchen sink, it’s likely that the problem can be remedied if you just focus on fixing that one fixture or the pipes serving it.

The first culprit to consider is the aerator. That’s the little screen fitting at the end of the faucet.  Mineral deposits can accumulate and eventually block the water flow at full expected force. 

If this is the case, simply remove the aerator and clean it out.  Flush it out, or soak it in a diluted vinegar solution overnight, and use a toothbrush to remove any lingering pieces.

Sometimes, the water pressure is low because the temperature limiter isn’t adjusted properly. The limiter is a plastic washer that you can adjust by hand after removing the faucet handle.  Each faucet brand has its own temperature limiter washer set up, so check your brand and find the particular instructions for your brand.

So, you’ve eliminated these possible causes.  Now What?

Low Water Pressure In a Single Faucet?

Focus on the fixture and the pipes feeding it.

What’s that mean?  Maybe it’s the faucet.  Faucets last for years, but they don’t last forever. If the internal parts go bad, the valves may not open completely, resulting in low or uneven water pressure.

As a final check before you remove the faucet to see if it’s the cause, check the water supply lines beneath the kitchen sink.  If you have children, perhaps one of them was turning the valve handles, that little imp.  Or the valve has developed a leak.  Valves, too, are not eternal.

Nothing there?  Okay, it’s probably the faucet.  Go back to those valves beneath the kitchen sink and turn the water supply off.  Then, open the faucet to release any water already in the pipeline, so to speak, and relieve pressure. 

Replacing an outdated faucet isn’t as difficult as you might think.

You can tackle the project with a basin wrench and a few other common tools. It should usually take no more than about an hour for the amateur DIYer. The same steps apply if you’re installing a new faucet onto a new sink. 

To give you an idea of the common steps for replacing a faucet, we found a very helpful video on YouTube from The Home Depot. You’ll find that video here.

What If My New Faucet Has Low Water Pressure, Too?

New Faucet Low Pressure

When installing a new faucet, sometimes debris is lodged inside of the cartridge holes. This debris may be from soldering, filing, or installing new piping. The cartridge holes allow water through the cartridge into the spout of the faucet. If the holes clog wholly or partially, there will be a lower water pressure until whatever is clogging the holes is removed.

Again, it’s a matter of cleaning out debris that is reducing water pressure from your faucet.

What Have We Learned About a Single Low Water Pressure Faucet?

The causes are few and relatively obvious.  As such, the cure is fairly obvious for each, as well.

  • Mineral deposits or debris.  Clean out the aerator/faucet using a vinegar solution and a toothbrush.
  • Faulty valve.  They don’t last forever and sometimes need to be replaced.
  • Leaks.  Check the line from the foundation wall to the faucet.
  • Neighborhood actions.  Hydrant flushing, broken water main, simultaneous neighborhood use – laundry, showers, etc.

Go down the list and eliminate causes until you find the culprit. Don’t be intimidated, though, by a faulty valve or its replacement.  It will take the amateur DIYer about an hour to replace and a plumber about 30 minutes.

Either way, it’s a solvable issue and a quick solution.

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