Bathtub & Shower Faucet Repair — DIY Guide & When to Call

A dripping bathtub faucet is one of those annoying plumbing problems that gets worse the longer you ignore it. A slow drip can waste hundreds of gallons a month, and the constant water flow eventually erodes the valve seat enough that no amount of DIY tinkering will fix it.

After 40 years of bathtub and shower repairs in Burleson and South DFW, I’ve worked on every brand and every type of valve. Here’s what every homeowner should know — what’s leaking, why, when you can fix it yourself, and when it’s time to call.

Types of Bathtub and Shower Valves

What you have under the wall determines how you fix it. The four main types:

1. Two-handle compression valve (older homes)

Separate hot and cold handles
Each handle controls a stem with a rubber washer
Common in homes built before the 1990s
DIY-friendly to repair — usually just a washer replacement

2. Single-handle cartridge valve (modern standard)

One handle controls both temperature and flow
A replaceable cartridge contains all the moving parts
Most homes built after 1995
Brands: Moen, Delta, Kohler, Pfister, Price Pfister
DIY-friendly if you can identify the brand

3. Pressure-balance valve (current code)

Single-handle, with added safety: maintains temperature when someone flushes a toilet or runs the dishwasher
Code-required in new construction since the 2000s
Repairs usually mean replacing the entire cartridge

4. Thermostatic valve (high-end)

Holds water at a precise temperature regardless of pressure changes
Found in upscale or remodeled bathrooms
Pricey to repair — usually a plumber call

Knowing which you have changes the repair entirely.

Common Problems and Their Causes

Faucet drips when off → worn washer (two-handle) or failed cartridge (single-handle)
Faucet won’t shut off completely → worn valve seat or stripped stem
Hot water mixes into cold (or vice versa) → failed cartridge
Low water pressure from shower head → mineral buildup in head or valve
Handle hard to turn or wobbly → stripped splines or worn stem
Water leaks behind the wall → cracked pipe or failed connection (NOT DIY)
Water on the floor near the tub → could be a shower pan leak, not the faucet
Tub spout drips when shower is running → worn diverter in the spout

DIY: Replacing a Cartridge in a Single-Handle Faucet

This fixes most modern bathtub/shower drip problems. The process varies a bit by brand but follows the same pattern.

Tools you’ll need:

Allen wrench set (for the handle set screw)
Phillips and flathead screwdrivers
Adjustable pliers
Cartridge puller tool (for stubborn cartridges — Moen and Delta sell brand-specific tools)
New cartridge (must match your faucet brand and model exactly)

Steps:

Shut off the water supply. Some homes have valves in the wall behind the tub or in an access panel. If yours doesn’t, shut off the main water at the meter.
Open the faucet to relieve pressure and drain remaining water.
Remove the handle. Look for a small set screw (Allen wrench) or a decorative cap that hides a Phillips screw. Save all hardware.
Remove the trim/escutcheon plate that covers the valve body — usually one or two screws.
Remove the retaining clip or nut holding the cartridge in place. Note the orientation of the cartridge — you’ll need to put the new one back the same way.
Pull the cartridge straight out with pliers (gently). If it won’t budge, you may need the brand-specific cartridge puller tool.
Insert the new cartridge in the same orientation. Reinstall the retaining clip.
Reverse the disassembly — trim plate, handle, set screw.
Turn water back on slowly and test for leaks. Run the faucet to verify the temperature direction is correct.

If hot is cold and cold is hot when you test, pull the cartridge and rotate it 180°.

DIY: Repairing a Two-Handle Faucet (Washer Replacement)

Older two-handle faucets are even easier to repair if you know which side is leaking. Listen and look — only the leaky side needs work.

Tools:

Phillips and flathead screwdrivers
Adjustable wrench or pliers
Replacement washer kit (universal kits cover most older valves)
Penetrating oil if needed

Steps:

Shut off the water supply.
Remove the handle (decorative cap, then Phillips screw underneath).
Unscrew the packing nut behind the handle with adjustable pliers.
Pull out the stem assembly. Inspect the end — you’ll see a flat rubber washer held by a small brass screw.
Replace the washer. Also replace any o-rings on the stem.
Re-assemble in reverse and turn the water back on to test.

Brand-Specific Notes

A few brands have quirks worth knowing:

Moen — Cartridges are notorious for sticking. Get the Moen cartridge puller tool (~$15) or be prepared to call a plumber. Lifetime warranty on most cartridges — call Moen with your model number for a free replacement.
Delta — Older Delta single-handle uses a rubber seat-and-spring kit that’s easier to replace than the full cartridge. Newer Delta uses cartridges.
Price Pfister / Pfister — Cartridges are unique to this brand. Lifetime warranty on parts.
Kohler — Premium parts, usually well-engineered. Some models use unusual cartridge styles.
Generic / off-brand — Often hard to find replacement parts. May make more sense to replace the whole valve.

If you don’t know what brand you have, look for the logo on the handle or trim plate. If there’s no marking and the faucet is 20+ years old, replacement may be smarter than repair.

Tub Spout & Diverter Issues

If your shower works fine but water drips out of the tub spout when the shower is running, that’s a worn diverter — the small mechanism inside the spout that switches water between tub fill and shower head.

For most tub spouts, the fix is replacing the entire spout — they’re cheap ($10–$30) and usually screw or slide on. A handy homeowner can do this in 15 minutes.

Shower Pan Leaks (Different Problem)

If you see water on the floor near the tub or shower but the faucet is working fine, you may have a shower pan leak — water getting past the waterproofing under the tile floor.

Symptoms:

Water staining on the ceiling below an upstairs shower
Damp baseboards near the shower
Loose tiles or grout that crumbles
Mildew smell near the shower

Shower pan leaks are NOT DIY territory. We can pressure-test the pan to confirm whether it’s leaking and recommend repair options.

When to Call a Plumber

Stop and call us if:

You can’t shut off the water to the valve
The cartridge is stuck and you don’t have the brand-specific puller tool
The valve body is corroded or pitted
There’s no shutoff valve for the tub/shower and you can’t shut off the main
You see water staining behind the wall or on a ceiling below
The valve type is thermostatic (high-end fixtures, complex repair)
You think it might be a shower pan leak rather than the faucet

When to Replace Instead of Repair

Replace the whole valve if:

The valve is more than 25 years old and giving repeated problems
Parts for your model are no longer manufactured
The valve body is corroded
You’re remodeling the bathroom anyway
You want pressure-balance code compliance for safety

Valve replacement usually involves opening the wall behind the tub. Not DIY-friendly. We do this all the time and can match your existing tile cutout in most cases. See our bathtub repair and replacement service for more.

A Word From Don

If you’ve tried the DIY steps and the leak persists, or you’re staring at a stuck Moen cartridge that won’t budge, give us a call. We work on every brand, and most bathtub/shower faucet jobs are same-day service on most plumbing calls. Free phone estimate before we head out.

Serving Burleson, Crowley, Joshua, Alvarado, Keene, Everman, and all of South DFW within about 20 miles of Burleson.

Call Don: 817-447-2654