Two different problems
The diverter is the part that sends water up to the shower head instead of out the spout. On many tub-showers it is a pull-up knob on the spout itself; on older three-handle valves it is the middle handle. When it wears, a lot of water keeps pouring from the spout while the shower runs, and shower pressure drops.
A spout can also leak at the back, where it threads or clamps onto the pipe coming out of the wall. Water that sprays back there runs behind the tile. That kind of leak is quiet and easy to miss until the wall below or behind shows damage.
What the symptom usually means
- IfWater pours from the spout with the shower diverter pulled upThenThe diverter gate inside the spout is worn; a new spout is the usual fix.
- IfThe middle handle of a three-handle valve leaks or won't divertThenThe diverter stem or its washer needs replacing in the valve.
- IfWater drips or sprays behind the spout when the tub fillsThenThe spout connection or the caulk joint at the wall has failed.
- IfThe spout wobbles or is loose against the wallThenIts connection has loosened; check behind it before water gets in.
How spout and diverter repairs go
- Identify the spout type.Spouts either slip on with a set screw underneath or thread onto a pipe. The connection type decides which replacement fits.
- Measure the pipe.The distance the pipe sticks out of the wall matters; a spout that doesn't reach or seat correctly can leak behind.
- Replace or rebuild.Diverter spouts are usually replaced whole. A diverter stem in a three-handle valve is rebuilt with a new stem or washer.
- Seal the wall joint.The gap between spout and tile is sealed so splashing can't run behind the wall.
- Run both ways.Fill the tub and run the shower to confirm the diverter fully switches and nothing leaks behind the spout.
What drives the cost
- Spout connection type and finish matching
- Whether the pipe stub is the right length or needs changing
- Whether the diverter is in the spout or in the valve
- Corrosion on an old galvanized pipe stub
- Any water damage behind the tile
Common questions
Can I replace a tub spout myself?
Often, if it is a slip-on or threaded spout and you match the type and pipe length. If the pipe stub is corroded or breaks, stop and call a plumber.
Why is my shower pressure weak only on the tub-shower?
A worn diverter lets much of the water escape through the spout. Fix the diverter before chasing pressure problems elsewhere.
Does a leak behind the spout need the wall opened?
Not always. If caught early, resealing the spout often stops it. Damage that has already spread may need the wall looked at.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.