How To Tighten Kitchen Faucet Nut Under Sink: Complete Guide

Don’t you hate it when water keeps dripping after you’ve turned off the kitchen faucet? While you may think this is a plumbing disaster, the issue is ridiculously easy to fix. You don’t even need plumbing experience. All you need is a handful of tools to fix the loose faucet.

To fix a leaky, loose faucet, you have to tighten the kitchen faucet nut located under the sink. Use a basin wrench or screwdriver with a long handle, depending on your faucet’s design, to turn the nut until it’s properly fastened. 

Loose Nut: The Reason Why Your Faucet Won’t Stay In Place

Kitchen faucets aren’t complicated, but mishandling can damage them easily. To understand why your kitchen faucet becomes loose over and over again, you have to understand its general construction.

All kitchen faucets have an under-sink bolt that couples the faucet’s base with its head. Like all bolts, this one is fastened with a nut, then held together by additional screws placed on each side.

While the additional screws hold the faucet in place even if the main nut becomes loose, the faucet might leak when this happens. 

The faucet’s nut might fail to stay in place due to an installation or manufacturing error. During installation, the plumber might overtighten the nut and damage the bolt’s thread. As you use the kitchen sink and move the faucet, the damaged threads will fail to keep the nut in place.

However, more often than not, the nut becomes loose because it wasn’t fastened tightly, to begin with. To fix the issue, you literally have to get under the sink and tighten it.

Tightening Tool Required

Sink fixtures usually come with everything you need to install them, except for instructions on how to tighten those hard-to-reach nuts. You needn’t worry, though, because we know exactly what tools you need for the job – and you don’t even have to write down a list because they’re few and easy to remember.

To tighten an under-sink faucet nut, you need: 

  • A basin wrench (an adjustable or open-end wrench might also work)
  • Adjustable pliers (optional)
  • Screwdriver (if your faucet has a screw instead of a bolt)
  • Headlamp or flashlight
  • Bucket (optional)

What size is a faucet nut?

Most faucet nuts have a diameter between 1 3/8 and 1 1/2 inches. When choosing a basin wrench, remember that most home improvement stores stock wrenches that fit nuts up to 1 or 1 1/4 inches; at this size, the wrench won’t fit the larger kitchen faucet nuts.

However, you can find adjustable or fixed basin wrenches suitable for nuts of all sizes. If your local store doesn’t have them, you could look for an appropriate model online. 

Depending on your sink’s design, you may also be able to tighten the nut with a standard wrench.

How To Tighten A Loose Faucet Nut Under Sink in 3 Easy Steps

Now that you know what tools you need and what size a faucet nut is, it’s time to learn how to tighten it (don’t worry, it’s really easy).

Step 1 – Clear the area beneath your sink

Tightening the faucet nut under your kitchen sink isn’t complicated, but you’ll need ample room if you want to succeed. Due to its placement, the nut is quite hard to reach – hence the need to use a basin wrench instead of an adjustable or combination one.

Take out everything stored in the cabinet under your sink and inspect the area. You’ll want to pay particular attention to the placement of the P-trap because this piece of plumbing can hinder access.

If you can’t reach the faucet nut because of the P-trap, you’ll have to remove it. To remove the P-trap: 

  1. Turn off the main water supply and place a bucket under the trap. Even though turning off the water is not necessary, doing so can help you avoid getting drenched if someone else opens the tap by mistake.
  2. Unfasten the ring nut connecting the P-trap to the tailpiece using a pair of pliers, then unfasten the ring nut connecting the trap to the wall drain pipe.
  3. Remove the P-trap and place it in the bucket. If necessary, you can clean it with soapy water and remove any clogs.

Step 2 – Adjust the position of the faucet 

A loose faucet can become misaligned, and you should center it again before tightening the nut. You could use an extra set of hands at this stage, so if you have a family member or friend close by, ask them to help.

Simply insert the fixture back into its hole, center it, and align it with the wall behind the sink. Have your helper hold the faucet steady while you pop under the sink to fasten the nut.

Step 3 – Tighten the kitchen faucet nut 

Put the headlamp on (or turn on the flashlight) and get under the sink. Locate the faucet’s bolt under the sink and its nut, then fasten it by hand as tightly as you can. 

At this point, position the basin wrench’s jaws around the nut and use the tool to fasten the nut the rest of the way. Keep turning the handle until the nut is tight, then have your helper let go of the fixture and check that it’s stationary.

Don’t fasten the nut too tight because you could damage the bolt’s threads. So, when you feel that the nut gets harder to turn, keep fastening a quarter-turn at a time and check if the fixture is stationary after each quarter-turn to figure out when to stop. That’s it! You can now enjoy your kitchen faucet once again.

Related Queries

As you’ve surely noticed by now, tightening an under-sink kitchen faucet nut is so easy that even the most inexperienced DIYers can do it. However, you may still have unanswered questions. Find the answers below.

Do you really need a basin wrench?

Technically, you could tighten an under-sink faucet nut with an adjustable, combination, or fixed wrench too. However, due to the position of the nut and the fact that you have to work in a confined space, a basin wrench is your best option.

If you’ve never heard of basin wrenches before, this tool has a flexible jaw that allows for easy positioning around the fastener. The jaws tighten automatically after you’ve positioned the wrench on the nut, holding a tight grip.

At the same time, a long handle with a T-handle at the opposite end allows you to turn the wrench by simply turning the handle (clockwise or counterclockwise, depending on whether you want to fasten or unfasten the nut).

Thanks to these features, a basin wrench helps you tighten the loose nut when working in tight spots or hard-to-reach areas.

How hard is it to replace a faucet?

Replacing an old kitchen faucet isn’t hard. In fact, the most difficult part is loosening the under-sink nut and removing the old faucet. 

Once that’s done, place the new fixture into the appropriate hole and follow the steps above to center, align it, and fasten the nut.


Loose faucets are a nightmare, but they are very easy to fix. The hardest part is figuring out how to reach the nut if you didn’t find the right size basin wrench and have to use a standard one. 

Have you ever dealt with loose faucets before? Do you have any tips or tricks on how to reach the nut under the sink? Tell us in a comment below.

Recent Posts