How to Replace a Faucet and Waste Line

Pro tricks to help you avoid those frustrating snags that aren’t covered in the directions

Replacing a bathroom faucet and waste line can quickly get complicated. Learn the shortcuts and tricks that professional plumbers use to make difficult installations go smoothly.

By the DIY experts of The Family Handyman Magazine

TIME

One day

COMPLEXITY

Moderate

COST

Under $20

Overview

A stylish new faucet may promise a quick, refreshing new look to your bathroom, but no one promises a trouble-free installation. In fact, the more expensive and fancy the faucet, the harder the install usually is. The printed directions supply you with the bare basics, but a horde of potential snags makes almost every job a complex one. The following tips will get you through the tough spots and save the $150 to $400 a plumber would charge for a house call like this.

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Before you dive in

Take off the vanity doors and lay a drop cloth
The cloth will save your flooring from tool scratches and contact with the disgusting debris that comes out of old pipes. It’s also worth taking a few minutes to unscrew the vanity doors and remove them for easier access. Tape the loose hinge screws to the doors so you don’t lose them.

Examine the underside of your sink for unsuspected leaks
Run water through the drain and check for any cracks or leaks that need to be repaired before you start your job. Also test the old P-trap by pushing a thumb on the underside as shown in Photo 1. If it’s soft, it’s high time to change it out— with plastic if it’s not in the public eye or with chrome if it’s exposed.

Pull out your new faucet and check the supply line connector
Supply lines usually won’t come with your new faucet (Photo 2). Take your new faucet with you when you buy supply lines to make sure you get the right connector size. Don’t trust the labels on the shelf; the supply lines tend to get mixed up. Pros prefer no-burst water supply lines made from flexible, braided stainless steel.

Loosen nuts to free stuck shutoffs
Water shutoffs are notorious for seizing up. Instead of bullying them loose, use a wrench to loosen the packing nuts behind the handles about a quarter turn (you’ll get a drip of water). That usually frees them (Photo 3). Turn on the sink faucet to be sure the water is completely off. If you still get drips, replace both shutoff valves.

Make a complete shopping list before heading to the store
Avoid numerous trips to the hardware store. The plumbing department should not be the place where everybody knows your name! Your shopping list should include two new supply lines (measure the length!), a small tube of 100 percent silicone, Teflon tape, a basin wrench and a P-trap if needed.

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Remove the old faucet

Clear the clutter to get at the basin nut
The instructions for your new faucet won’t include how to get the old faucet out, so you’re on your own with that. Start by removing the supply lines to clear out the clutter. Your faucet will be held in place under the sink by some sort of nut. If you’re lucky, you can reach it with an adjustable wrench. (Remember that you’ll be working upside down, so take a moment to make sure you’re turning the nut in the correct direction—counterclockwise.) Or if you’re really lucky, you can hand-loosen a plastic nut.

Get at inaccessible faucet nuts with a basin wrench
But chances are that you won’t have enough space to get the wrench in. Next, reach for a basin wrench (Photo 4). A basin wrench has an extension that allows you to reach up into tight spots that you can’t get to with a regular wrench. Use your hand to guide the wrench teeth onto the nut while you twist the handle counterclockwise from below. Using this tool can be an awkward and humbling experience, so don’t worry if you fumble around a bit. This tool really works!

As a Last Resort, Buy a Nut Splitter

If the nut seizes up completely, as corroded “pot metal” ones often do, you’ll have to use a nut splitter to break it off (Photo 5). Get one at a plumbing or auto parts store for about $30. Buy the size that fits the faucet threads. A length of pipe will help you apply extra torque. Screw the splitter onto the threaded section of faucet with the teeth pointing upward. Using the ratchet, drive the cutting teeth into the nut. This will split the nut in half and it’ll pop apart (Photo 6).

Photo 5: Using a nut splitter
Photo 6: Nut splitter
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When the pop-up won’t pop out

The pop-up assembly consists of a flange (the part you see in the sink) that screws into a body (the part below the sink as shown). If you’re lucky, you can simply grab the body (you left the rod on for extra torque) and turn it counterclockwise to unscrew it. Unfortunately, most of the time the flange in the basin also turns, so it won’t come apart. At other times it simply won’t turn.

Cut a stuck pop-up assembly with a hacksaw
If you’re alone, the best solution is to cut off the pop-up body from below. Unscrew the locknut, if possible, and cut the stuck pipe above the nut with a hacksaw (Photo 7). This is difficult work, but be persistent. Once the pipe is cut, you can pry out the flange.

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Installation can be challenging

Dry-fit the new faucet
The new faucet directions are primarily written for new construction, where you install the faucet before the sink goes in and you have plenty of work (wrench) space. In your home, you’ll run into tight spots where the instructions, followed to the letter, simply won’t work (Photo 8). Remove the handles and spout and set the faucet body into the sink holes to see if it will go in exactly according to the directions. Check the connection methods and adjustment features, tool access for tightening various nuts and handle and spout seating on the sink top. They should fit flat without rocking.

Be prepared to improvise
In our case, there was no way to fit the basin wrench, or any other tightening tool, onto the spout nut. The faucet body was in the way (Photo 10). We ended up disassembling parts of the faucet body to give us an easy shot with a wrench to tighten up the spout assembly (Photo 11). Aligning the spout and faucet assembly washer was also critical after tightening the spout. We had to square up the washer by holding a screwdriver on it and tapping with a hammer.

Study the directions and don’t hesitate to call the manufacturer for help. Even the pros do it, especially on high-priced (complicated) faucets. Try to find a way around the problem before tossing it all back into the box.

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Getting the new pop-up perfect

“Overflow” the flange with silicone
The flange at the bottom of the sink is a common leak point. During the manufacturing process, the sink drain hole may be over-buffed or cast more in the shape of an egg than of a flat circle. The leak-free solution is to overflow the flange and the area beneath it in the sink with a bead of 100 percent silicone (Photo 12) . This will fill in any factory irregularities in the basin. Press the flange into the drain hole and screw the pop-up body on from below. Then tighten the locknut (Photo 13). For a white basin, white silicone will look best. Otherwise use clear. Quickly wipe off the excess before it dries and becomes a hassle to clean up.

Bend the metal strap so you can clip it farther up the horizontal rod
This will shorten the stroke to raise and lower the stopper (Photo 13).

Tinker with the pivot arm for a smooth operating pop-up
Insert the horizontal arm and stopper into the pop-up body and hand-tighten the packing nut. Slide the metal strap onto the lift rod (handle) and then clip it onto the horizontal rod. Tighten the lift rod setscrew and test the pop-up action. Tighten the packing nut. There’s a fine line between a leaky packing nut and a too-stiff pop-up. You’ll have to experiment.

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Leak check

Check for leaks with toilet tissue
Wipe the valve stem/packing nut zone completely dry and wrap with toilet tissue (Photo 15). Turn on the water and check for obvious leaks at all the connection points. After 10 minutes, check the tissue. If the tissue is damp, tighten the packing nuts or replace the packing or entire valve.

Switch to a plastic P-trap
If your chrome P-trap is in good shape, you can reuse it, but replace the rubber washers. If the trap is out of sight, we recommend switching to a plastic P-trap. They’re inexpensive and less likely to leak. Also install new flexible supply lines. Now you’re ready to turn the water back on. Remember to retighten the packing nuts behind the oval handles on the shutoff valves if you loosened them earlier.

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver
  • Adjustable wrench
  • Hacksaw
  • Slip joint pliers
  • Wrench set

You’ll also need a basin wrench, trouble light, canvas drop cloth and a nut splitter.