If you’ve noticed a slow leak beneath your bathroom sink, it could be a rusted pipe nipple (i.e., nipple pipe fitting) that you’ll need to address before the leak gets worse. The job involves removing the shut-off valve, so if it’s old, you might want to go ahead and replace the water shut-off valve under your bathroom sink as well. Keep reading or watch the video below.

Even if a leak hasn’t started yet, if the pipe nipples attached to the supply tubes are old or the shut-off valves are missing, you’ll want to replace/install them. That’s because a deteriorated pipe nipple can easily break and cause leaks. Additionally, shut-off valves are helpful because they allow you to repair plumbing fixtures without needing to turn off the water supply to your entire home.  

Replace Pipe Nipples and Water Shut-Off Valves

1 – Examine the supply tubes (ie., supply lines) under the bathroom sink. If there are no shut-off valves extending out of the wall (where the supply tubes connect), you’ll want to install them. In order to install them safely, you’ll need to find your main emergency water shut off and turn off the water to your entire home.

2 – The nipple fittings are located behind the supply tube, so you’ll have to remove the supply tube to install the new nipple. (If you have an older home built in the 1950s, you’ll likely need a 3/8″ pipe nipple). Note: since you need to remove them, you should consider replacing the entire supply tube, especially if it’s old.  

3 – Remove the first supply tube by unscrewing it from the wall with your hands. 

4 – After removing the tube, use channel locks to remove the adaptor that’s coming out of the wall. Next, remove the escutcheon plate, which should come off easily with your hands.

5 – If the nipple pipe fitting is old and galvanized, it might remain stuck inside the wall. If so, pull it out with channel locks or a wrench and nipple extractor (if the pipe nipple is very corroded).  

6 – Repeat this process for the second supply tube.

7 – Apply Teflon plumbing tape to the threads of the new pipe nipples on both ends. Leave the first few threads exposed so it will be easier to tighten the pipe nipple in place.

8 – Clean escutcheons with Scotch Brite. 

9 – Paint the threads on one side of the pipe nipple with pipe dope. Apply it right over the Teflon tape all the way around the threads. (Wait to apply pipe dope to the other side of the nipple fitting so you can tighten it by hand with minimal mess.)

10 – Put the side of the pipe nipple that you painted into the mount, then screw the nipple back into the wall, tightening it by hand.

11 – The pipe nipple should now be protruding from the wall. Paint over the remaining Teflon-taped threads with pipe dope. 

12 – Manually screw the water shut-off valve over the pipe nipple. Finish tightening it with a wrench.

13 – Connect the supply tube to the water shut off valve. Manually screw it in place, then tighten the nut with a wrench.

14 – Turn the water to your home back on.

Turn On Faucet to Test Sink

1. Once you’ve replaced the pipe nipples and water shut-off valve, turn the faucet on to make sure all fixtures are working properly.
2. If your water pressure seems low, remove the faucet aerator to see if any sediment has built up from the old galvanized pipe nipples.
3. Rinse any sediment off of the faucet head, and screw it back into place.

If you’re having difficulty replacing your water shut-off valve or need help with leak detection in Baltimore County or the surrounding areas, connect with an expert plumber in Ellicott City, MD.

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Heil Plumbing is a family-run company owned by a third-generation master plumber. We can help you with a full range of plumbing services, including toilet installation and repair, leak detection and pipe repair, water heater repair and installation, faucet repair and installation, drain cleaning, water treatment, and more.