Start by asking when the water appears. If it appears only while the shower runs, suspect the valve, the arm, the pan or the grout. If it keeps showing with the shower idle, a feed line within the wall is leaking, and the water should go off. Kitchen fixtures are the same trade; the garbage disposal repair page covers the sink side, and a disposal install is explained further down.
How do I tell where a shower leak is coming from?
Narrow it with three tests. Run the shower and watch for water below it. Plug the drain and fill the pan with an inch of water for a day to test the pan and drain. Close the supply to the shower and see whether dripping continues, or read the meter, to test the pipes.
What each result points to:
| Test result | Likely source |
|---|---|
| Leak only when water is running | Valve, shower arm, grout, door or curtain |
| Leak when the pan is filled and the drain plugged | Pan, drain flange or drain connection |
| Leak while the shower is off | Supply pipe or valve body inside the wall |
| Stain appears below only after long showers | Grout, caulk or pan edge |
Water in a ceiling below the bathroom travels along framing, so the stain can be far from the leak. For ceilings, see water leak in a ceiling and signs of a ceiling leak.
What does a plumber repair in a leaking shower?
Depending on the source: replace a cartridge or valve, reseat the drain flange, repair a shower arm connection, fix a supply pipe in the wall, or point the job to a tile or waterproofing specialist when the pan or membrane has failed. A plumber handles pipes and valves. Tile, grout and pan waterproofing often fall to a tile contractor.
A dripping handle or spout generally usually means a tired cartridge or washer; the repair steps are in the shower faucet fix and the tub faucet fix. Hard water speeds the wear. Moulton Niguel Water District reports hardness near 9 to 18 grains by source, and scale roughens cartridges and clogs shower heads. When a wall has to be opened, ask if patching and tile are in the quote. Faucet-level costs are on faucet replacement cost.
What if a shower pipe has burst?
Turn the house main off, empty the lines at a low faucet, then phone for help. A pipe that bursts behind a shower wall soaks framing fast, and fixing it means opening the wall. Cold weather is rarely the cause in Mission Viejo; pressure, corrosion and old fittings are the usual reasons.
Photograph everything for the insurer, then start drying. Hidden damage can continue after the water is off, so ask about moisture checks before closing the wall. For a general walk-through see the page on leaks in Mission Viejo homes. If the shower pipe is old copper, repeated pinholes may point toward a bigger repipe discussion.
Why is there no pressure at the tub when everywhere else is fine?
When only one fixture is weak, think of a clogged shower head or aerator, a stop valve opened only part way, a worn diverter or a cartridge on its last legs. Hard-water scale often lies behind it. Soak the unscrewed shower head in vinegar, inspect the diverter, and note the flow from the spout versus the head.
When spout and head are both weak yet other fixtures run fine, points to the cartridge or the supply feeding that valve, and a plumber can open the valve body to see. If every fixture is low, the issue is pressure at the house, not the tub; see low shower pressure.
How is a garbage disposal installed?
In outline: cut power, remove the old unit or the sink strainer, attach the new mounting assembly to the sink flange, hang the disposal on the mount, connect the drain and the dishwasher hose, and wire it or plug it in. Follow the manufacturer's manual, because mounting systems differ across brands such as InSinkErator, Glacier Bay and American Standard.
Common mistakes: forgetting to knock out the dishwasher inlet plug, which makes the dishwasher back up; a leak at the sink flange from too little plumber's putty; and a poor trap connection. Hard-wired units need an electrical connection, and some cities treat changes to wiring as permit work. Ask Building Services if unsure. A plumber can also handle the drain and trap. See garbage disposal installation service for details.
What is different about sink plumbing in a mobile home?
A mobilehome sits under state housing rules, not only city ones. According to HCD, the state housing department, installing or altering plumbing in mobilehomes and parks takes a written permit, and either HCD or a local agency inspects. Swapping in equivalent original parts typically needs no permit.
Fixtures often connect to smaller or flexible supply lines and to a drain system sized for the unit, so a standard disposal or faucet swap should be checked against the manufacturer's instructions and the home's setup. Before altering plumbing, check with the park or HCD about the permit. An inspection overview is at mobile home plumbing inspection.
At what point do I call someone, and what will it cost?
Pick up the phone when the leak is in the wall, the shower drips when idle, the source stays hidden, or tile has to come off. A cartridge swap is brief, whereas wall access and tile push the price up. Your number arrives in writing after a visit.
State rules cap a deposit for home improvement work, and CSLB puts the contractor license line at $1,000 of work, so look the number up. The price request page is where you describe the leak, and a local plumber follows up in person. Remodeling the bathroom? Plumbing changes are discussed in bathroom remodel plumbing. The Capistrano Plumbing home page explains how visits work.
Common questions
Can a shower leak damage the ceiling below?
Yes. Water takes the lowest route, often through a pipe hole or along a joist, then shows up below as a stain, bubble or drip. Slow leaks can go unseen for weeks. Stay out of the shower until the source is known, and have the area checked for moisture before it is covered up.
Does a dripping shower head need urgent attention?
Not by itself. A dripping head usually means a worn washer or cartridge, or scale, and it wastes water without being an emergency. EPA reckons easy-to-fix leaks cost the average home over 9,300 gallons yearly, which is reason to deal with it soon. Water inside a wall or a spreading stain is more urgent.
Can I reseal the grout myself to stop the leak?
Regrouting and recaulking help when water is getting through failed surface joints. They do nothing for a leaking valve, supply pipe or pan, so run the pan and drain tests first. If the stain comes back after resealing, the source was something else, and a plumber should look.
Is a permit needed when the shower valve is replaced?
Swapping a cartridge usually does not require one. Replacing the whole valve or moving pipes may, depending on the city's rules for the work. Call Mission Viejo's Building Services Division before starting, and check that any plumber quotes the permit and follow-up inspection too.
Should I use the disposal with a leak under the sink?
Stop using it and cut power at the switch or breaker. The usual suspects are the sink flange, the drain and the dishwasher hose. Dry the cabinet, find the wet joint and fix it first, since wet wiring is a hazard. Avoid running the disposal until the cabinet floor stays dry.
Sources
Updated