How to Replace a Shower Valve

A dripping shower head, a handle that's hard to turn, or water that suddenly goes scalding when someone flushes a toilet: all of these point to the shower valve. The good news is that many shower problems are fixed by replacing the cartridge inside the valve, which takes an hour or less and doesn't involve opening the wall. Replacing the whole valve body is a bigger job. This guide helps you figure out which one you need, explains pressure-balance vs thermostatic valves, and walks through the steps, including how to connect the new valve with solder, PEX or press fittings and when to call a plumber.

Cartridge or full valve: which do you need?

A shower valve has two main parts: the valve body (the brass rough-in piped into the wall) and the cartridge or stem (the removable part that controls flow and temperature). The trim is the visible handle, escutcheon plate and spout.

Replace just the cartridge if:

• The shower head or tub spout drips after the handle is off.
• The handle is stiff, loose or hard to turn.
• Temperature is hard to adjust, or you can't get enough hot or cold water.
• The valve body itself isn't leaking and you're happy with the brand and trim style.

Replace the full valve if:

• The valve body is cracked, corroded or leaking inside the wall.
• The cartridge is no longer made, or the valve is too old to identify.
• You want to change brands or trim styles. Trim usually only fits the same manufacturer's valve body, often the same series.
• You have an old two- or three-handle valve and want to upgrade to a single-handle anti-scald valve.
• You're remodeling and the wall is already open.

Pressure-balance vs thermostatic valves

Most US plumbing codes require individual shower and tub/shower valves to provide scald protection. That means a pressure-balance, thermostatic or combination valve listed to ASSE 1016 / ASME A112.1016 / CSA B125.16. The two main types work differently:

Whichever you choose, set the handle's rotational limit stop during installation. Plumbing codes commonly cap the maximum outlet temperature at 120°F, and the limit stop keeps the handle from turning past that point.

Find access to the valve

Before buying parts, figure out how you'll reach the valve:

• Access panel: Many homes have a removable panel on the other side of the shower wall, in a closet or hallway. This is the easiest way to replace a full valve without disturbing tile.
• From the shower side: Without an access panel, you'll need to open the wall around the valve. Cutting through tile is the hardest part of the job. A large remodel or "cover" plate can hide a bigger opening if you keep the hole small and neat.
• Install an access panel afterward: If you open drywall from behind, finish it with a removable access panel so future repairs are easier.

Shut off the water

1. Look for integral stops on the valve itself. Many valves have small screwdriver-slot shutoffs on the hot and cold inlets, visible once the trim is off.
2. If there aren't any, close the branch shutoffs serving the bathroom, or the main shutoff for the house.
3. Open the shower and a lower faucet to drain the lines and relieve pressure.
4. For electric or gas water heaters, follow the manufacturer's guidance if you'll have the water off for a long time.

How to replace a shower cartridge

1. Note the brand and look for a model number on the trim, valve or cartridge. Take photos.
2. Remove the handle (usually a set screw under a cap) and the escutcheon plate.
3. Remove the retaining clip, nut or bonnet that holds the cartridge in place.
4. Pull out the old cartridge. Some brands need a cartridge puller. Note which way it faces, because many cartridges have hot/cold orientation marks.
5. Clean the valve body bore and check the seats and springs (on valves that use them).
6. Lubricate O-rings with silicone plumber's grease if the manufacturer recommends it, then install the new cartridge in the same orientation.
7. Reinstall the clip or nut, turn the water on, and check for leaks and correct hot/cold direction before you reinstall the trim.
8. Set the limit stop, then reinstall the escutcheon and handle.

Cartridges, stems, seats and springs for many brands are in our tub and shower repair parts collection. Match the part to your valve's brand and model.

Repairing a Moen shower? Our guide Which Moen Cartridge Do I Need? 1222 vs 1225 vs 1200 vs Posi-Temp shows how to identify your cartridge by the way the handle works.

How to replace a full shower valve

1. Open the wall through the access panel or around the valve.
2. Shut off and drain the water as described above.
3. Cut out the old valve with a tubing cutter, leaving enough straight pipe for the new connections. On threaded galvanized or brass, unscrew the fittings instead.
4. Set the new valve at the right depth. Every valve has a range of rough-in depth from the finished wall surface. Use the plaster guard or depth gauge that comes with the valve, and allow for tile, backer board and mortar thickness.
5. Secure the valve to blocking or a mounting bracket so it can't move when the handle is turned.
6. Connect hot, cold and outlets (shower riser and tub spout) using one of the methods below. Hot goes on the left, cold on the right, unless the valve's instructions say otherwise.
7. Pressure test before closing the wall. Most valves include a test cap or plug. Turn the water on and check every joint.
8. Close the wall, finish the tile or panel, and install the trim, limit stop and handle.

If your tub spout uses a slip-on or threaded connection, check the spout manufacturer's required pipe length from the valve. Getting it wrong can cause leaks or a spout that doesn't sit flush.

Soldering vs PEX vs press connections

Most valve bodies come with sweat (solder), threaded (IPS), PEX or press inlets, or with universal inlets and adapters. Choose a method that matches your existing pipe and your skills.

• Soldering (sweat copper): The traditional method. Strong and permanent, but it needs an open flame inside a wall. Remove the cartridge and any plastic parts before soldering, per the valve instructions, so the heat doesn't damage seals. Use a flame shield and keep a fire extinguisher nearby.
• PEX: Flexible, fast and flame-free. Valves with PEX inlets or PEX adapters work with expansion (ASTM F1960) or crimp/clamp (ASTM F1807) fittings. Use the fitting system that matches your tool and your pipe. Secure PEX near the valve so it can't move. Many codes and manufacturers require copper or a drop-ear elbow for the shower riser and tub spout, so check the valve instructions.
• Press fittings: Press copper or press PEX fittings make a sealed joint in seconds with a press tool, with no flame, and they're more forgiving than solder of a little water left in the line. Great for repairs inside finished walls, but the tool is a significant investment unless you can rent or borrow one.
• Threaded (IPS): Used with brass or galvanized nipples. Use the thread sealant the manufacturer recommends, and don't overtighten into the valve body.

Shop PEX adapters, elbows and stub-outs in our PEX fittings collection.

When to call a plumber

• You'd have to cut through tile without an access panel and aren't comfortable repairing it.
• Your home has old galvanized steel pipe, which often crumbles or leaks when disturbed.
• There are no working shutoffs, or the main shutoff doesn't fully stop the water.
• You'd need to solder near wood framing, insulation or other combustibles and haven't done it before.
• Your area requires a permit or a licensed plumber for valve replacement. Many do for anything beyond a cartridge.
• You're converting to a thermostatic system with multiple outlets, body sprays or a larger supply line.
• After the repair, temperature still fluctuates, or the valve leaks into the wall.

Before you order

• Identify the valve brand and series. Look on the trim, cartridge or valve body, or compare photos with the manufacturer's identification guides.
• Decide on pressure-balance or thermostatic, and how many outlets you need.
• Confirm the connection type (sweat, PEX, press or IPS) and the rough-in depth for your wall.
• Choose trim that's compatible with your valve body.

Browse our shower and tub-shower valves, then pair them with matching tub-shower trim sets. Need help matching a cartridge or trim to your valve? Send us the brand and any numbers you can find, plus a photo, and our team will help you track down the right part.