A dripping bathtub faucet wastes water and stains the tub, but replacing it is a job most homeowners can finish in an afternoon. You do not need a plumbing license, just the right tools and a little patience.
Before you buy anything, figure out what you are dealing with. Is the whole valve leaking, or just the spout? Do you have a slip-on spout or a threaded one? This guide walks you through both, from shutting off the water to sealing the new fixture so it lasts.
Key Takeaways
- Shut off the water first: Close the isolation valves behind the tub access panel or the main shut-off, then open the handles to drain the lines before you touch anything.
- Identify your spout type: A slip-on spout slides onto a copper pipe and locks with a hidden set screw; a threaded (IPS) spout screws directly onto the pipe. They are not interchangeable without an adapter.
- Match the parts before buying: Take the old stem and spout to the store so the spline count and length match, or buy a universal trim kit that includes adapters.
- Seal, but leave a weep gap: Caulk the top and sides of the spout and handle plates, and leave the bottom open so a hidden leak can drain instead of rotting the wall.
Tools You Will Need
Replacing a faucet is straightforward, but you need the right gear. Gather these items before you start:
- Flathead and Phillips screwdrivers
- Tongue-and-groove pliers (Channellocks)
- Socket wrench set (for faucet stems)
- Allen wrench (Hex key) set
- Plumber’s tape (Teflon tape)
- Utility knife
- Silicone caulk and caulk gun
How to Remove the Old Faucet
1. Turn Off the Water Supply
Start by cutting the water supply to the bathtub. If you have an access panel behind the tub, look for the isolation valves there.
Most homes rely on main shut-off valves typically found in the basement, utility room, or near the water meter. If you are unsure where yours is, ask a professional to help you locate it.
Keep In Mind
2. Drain the Lines
Open the bathtub faucet handles to let the remaining water flow out. This relieves pressure and helps drain the faucet. Once the flow stops, close the handles.
3. Remove the Handle Caps
Most faucet handles have a decorative plastic or metal cap in the center. This hides the screw holding the handle to the wall.
Use a small flathead screwdriver to gently pry this cap off. Be careful not to scratch the finish if you plan to reuse the handles.
4. Unscrew the Handles
Plug the tub drain with a rag or stopper. This prevents loose screws from falling down the drain, which is a headache you want to avoid.
Use a screwdriver to remove the center screw by turning it counterclockwise. If your faucet has a separate cover plate (escutcheon) against the wall, check for screws there too. Place all hardware in a bowl or bag so it doesn’t get lost.
5. Remove the Stem (Cartridge)
The stem, or cartridge, is the mechanism inside the wall that controls water flow.
You might need a socket wrench specifically designed for plumbing (a shower valve socket wrench) to reach the nut holding the stem in place. Slide the socket over the stem and turn counterclockwise. Once the nut is loose, pull the stem straight out.
6. Remove the Spout
Removing the tub spout is where many people get stuck because there are two different attachment styles. Check underneath the spout near the wall first.
Slip-on Spouts: Look for a small notch underneath containing a set screw. Use an Allen wrench (hex key) to loosen this screw. You do not need to take the screw all the way out. Once loose, pull the spout firmly off the copper pipe.
Threaded (IPS) Spouts: If there is no screw, the spout is threaded. You simply twist the entire spout counterclockwise like a jar lid.
Take Note
7. Clean and Measure
Scrape off old caulk from the wall using a utility knife. Clean the copper pipe (nipple) sticking out of the wall.
Measure the length of the pipe extending from the wall. This measurement is critical. If your new spout is too short or too long for the pipe, it won’t fit flush against the wall.
How to Install the New Faucet
1. Choose the Right Replacement
Take your old stems and spout to the hardware store. Matching the size and spline count (the grooves on the stem) is essential for a proper fit.
If you are changing the style, buying a universal trim kit is often the easiest route. These kits usually include adapters to fit various valve types.
Upgrading The Valve?
2. Install the New Stems
Insert the new stem into the valve body in the wall. Thread it in by hand first to avoid cross-threading. Once it catches, use your socket wrench to tighten it snugly.
Be Careful
3. Attach Handles and Trim
Slide the new cover plates (escutcheons) over the stems. Push the new handles onto the stem splines. Insert the handle screw and tighten it down. Snap the decorative cap over the center.
How to Install the Spout
1. Prep the Pipe
If you have a threaded pipe (iron pipe size), wrap plumber’s tape clockwise around the threads sticking out of the wall. Wrap it three or four times. This tape lubricates the connection and creates a watertight seal.
If you have a smooth copper pipe (slip-on style), verify the pipe is free of burrs or sharp edges that could cut the O-ring inside the new spout.
2. Attach the Spout
For Threaded Spouts: Screw the new spout onto the pipe clockwise. Tighten it by hand until it is snug and the opening faces straight down. If you need a wrench to tighten it, wrap the spout in a towel to prevent scratches.
For Slip-on Spouts: Slide the spout over the copper pipe until the base touches the wall. Tighten the set screw underneath with your Allen wrench.
3. Seal with Caulk
Once everything is installed and tested for leaks, apply a bead of silicone caulk around the top and sides of the spout and handle plates where they meet the wall.
Leave a small gap at the very bottom of the spout and plates. This “weep hole” allows water to escape if a leak develops behind the wall, alerting you to the problem before rot sets in.
