What You Need to Know Before You Start

Replacing a Delta tub faucet is a job most homeowners can do in an afternoon with basic tools — no plumber required. The process differs slightly depending on whether your Delta faucet is a single-handle, double-handle, or cartridge model, but the core steps are the same: turn off the water, remove the old faucet, and install the new one. The hardest part is usually getting the old faucet loose if it has been in place for years.

Before you buy a replacement, check what type of faucet you have now and measure the distance between the hot and cold water supply lines under the sink. Delta faucets come in different configurations — some mount on the deck (the tub rim), others on the wall. Knowing which one you have saves a trip back to the store.

Key Takeaways

  • Turn off the water at the shutoff valves under the sink or at the main water line before you remove anything.
  • Most Delta tub faucets use a cartridge or compression valve that you can access by removing the handle and trim ring with basic hand tools.
  • Measure the distance between your hot and cold supply lines so you buy a faucet that fits your existing plumbing.
  • Use plumber's tape on all threaded connections when you install the new faucet to prevent leaks.
  • Test for leaks at both the faucet base and the supply connections before you close up the wall or seal the deck.

Gather Your Tools and Materials

You will need an adjustable wrench, a Phillips and flathead screwdriver, plumber's tape (also called thread seal tape or PTFE tape), a bucket or towel to catch water, and possibly a faucet puller if the old faucet is stuck. A headlamp or flashlight helps because you will be working under the sink in dim light.

Have the new Delta faucet on hand before you start, along with any gaskets or washers that came with it. Read the installation instructions that came in the box — Delta includes them with every faucet, and they show the exact sequence for your model. Keep the old faucet nearby until the new one is fully installed and tested, in case you need to reference how the connections were arranged.

Turn Off the Water and Drain the Lines

Locate the shutoff valves under the sink — there should be one for hot water and one for cold. Turn both clockwise until they stop. If the valves are stuck or missing, you will need to shut off the main water supply to the house. Open the faucet to release any remaining pressure in the lines, then place a bucket or towel under the connections to catch drips.

If water still flows after you close the shutoff valves, the valves are faulty and you must turn off the main supply. This is a sign those valves should be replaced at the same time — ask a plumber about this if you are not comfortable doing it yourself.

Remove the Old Faucet

From under the sink, locate the supply lines connected to the faucet. Use the adjustable wrench to loosen the nuts that hold them — turn counterclockwise. Once the supply lines are free, look for the bolts or nuts that hold the faucet body to the deck or wall. These are usually on the underside of the faucet, accessible from below the sink. Remove them with your wrench.

If the faucet will not budge, spray the connections with penetrating oil and wait 15 minutes. Tap gently with a hammer to loosen corrosion. Do not force it — a cracked fitting under the sink is expensive to repair. Once the faucet is loose, pull it up and out from the deck or wall. Clean away any old caulk or putty with a scraper so the new faucet sits flush.

Install the New Delta Faucet

Position the new faucet in the same holes as the old one. If the holes do not line up, you may need to drill new ones or use a faucet escutcheon (a trim ring) to cover gaps. Slide the mounting bolts through the faucet body and tighten them from underneath with your wrench — snug but not so tight that you crack the faucet. The faucet should sit level and stable.

Connect the hot and cold supply lines to the faucet inlets. Wrap plumber's tape clockwise around the threaded connection on the faucet inlet three to four times before you screw the supply line nut on. This prevents leaks at the connection. Tighten the nuts by hand first, then use the wrench to snug them — again, firm but not crushing. If you over-tighten, you can crack the fitting or strip the threads.

Seal and Test for Leaks

If your faucet mounts on the deck, explore a bead of silicone caulk around the base where it meets the tub or counter. Smooth it with a wet finger. Let it cure for 24 hours before you use the faucet. Wall-mounted faucets do not need caulk.

Turn the shutoff valves back on slowly — open them a quarter turn, wait a few seconds, then open them fully. Turn on the faucet and let water run for 30 seconds to flush air from the lines. Check under the sink for drips at the supply line connections and at the faucet body. If you see water, turn off the shutoff valves and tighten the leaking connection another quarter turn with your wrench. Repeat the test. Small drips often stop once the connection has been tightened and water pressure has stabilized.

Common Problems and How to Fix Them

If water leaks from the handle, the cartridge inside may be faulty — this is a Delta part you can order and replace without removing the whole faucet. If water leaks from the spout when the faucet is off, the cartridge seal is worn and needs replacement. Both are easier fixes than replacing the entire faucet.

If the new faucet does not fit your existing holes, you have three options: drill new holes (requires a drill and steady hand), use a faucet escutcheon to cover the gap, or remove the old faucet trim ring and install a new one that matches your new faucet. Delta sells trim rings separately if you need one. If you are not confident drilling into tile or stone, a plumber can do this in 30 minutes.

Frequently Asked Questions

Do I need to turn off the main water supply if I have shutoff valves under the sink?

No, shutoff valves are designed for this purpose. Turn both the hot and cold valves clockwise until they stop. If the valves leak or do not shut off the water completely, you will need to use the main supply instead. This is a sign those valves should be replaced.

What is the difference between a Delta cartridge faucet and a compression faucet?

A cartridge faucet has a single valve inside the handle that controls both temperature and flow. A compression faucet has separate hot and cold handles, each with its own valve. Delta makes both types. Check your old faucet to see which one you have, then buy a replacement of the same type so the supply lines fit.

Can I replace just the cartridge instead of the whole faucet?

Yes. If your Delta faucet is leaking from the spout or the handle is hard to move, the cartridge inside is likely worn. You can order a replacement cartridge from Delta or a hardware store, remove the handle and trim ring, and swap it out in 10 minutes. This costs far less than a new faucet.

How long does it take to replace a tub faucet?

Most replacements take one to three hours, depending on how stuck the old faucet is and whether the new one fits the existing holes. If the old faucet is corroded or the holes do not line up, add extra time. Caulk must cure for 24 hours before you use the faucet.

What if water is still leaking after I tightened the connections?

Turn off the shutoff valves, loosen the leaking connection completely, and wrap the threaded part with three more layers of plumber's tape. Reconnect and tighten again. If it still leaks, the threads may be damaged — you may need a new supply line or a plumber to assess the fitting.