Bathroom Plumbing in San Jose, CA
The bathroom plumbing you cannot see: the shower valve, the tub and shower drains, the vanity supply and drain, and the vent that lets it all flow. Most of it lives behind tile.
Signs you need this
Behind the tile
A shower that runs scalding or cold when a toilet flushes usually has an older valve without pressure balancing. Replacing it means opening the wall behind the valve, from the other side when there is access, or through the tile when there is not.
A ceiling stain under a bathroom usually traces to the shower pan, a drain connection, or a supply line in the wall. Tell us whether the stain grows when the shower runs or when the tub fills. That narrows it before anything gets opened. If you cannot tell where it is coming from, start with leak detection.
Tell us whether the stain grows when the shower runs or when the tub fills. That narrows it before anything gets opened.
Remodel rough in
In a remodel, the drain, vent and supply go in while the studs are open, and they get inspected before the wall closes. The photos on this page are one of our bathroom rough ins at that stage: drain and vent in black ABS, copper supply lines, and the shower valve capped. San José requires a plumbing permit to repair or replace the drain piping inside a building, per City of San José Bulletin #276.
A running or rocking toilet is its own job, covered under toilet repair. A dripping faucet or shower head is faucet and fixture repair.
How the job runs
- 1Find the leak or the failed valve before opening anything
- 2Open the smallest area that reaches it
- 3Repair or replace, then test under pressure
- 4Close up, or leave it open for the inspection on a remodel
Questions people ask
Why does my shower turn hot or cold when someone flushes?
That usually means an older shower valve without pressure balancing. Replacing it means opening the wall behind the valve, from the other side when there is access, or through the tile when there is not.
What causes a stain on the ceiling under a bathroom?
Usually the shower pan, a drain connection, or a supply line in the wall. Tell us whether the stain grows when the shower runs or when the tub fills, which narrows it before anything gets opened. If you cannot tell, start with leak detection.
Can bathroom plumbing be moved in a remodel?
Yes. The drain, vent and supply go in while the studs are open, and they are inspected before the wall closes. San José requires a plumbing permit to repair or replace the drain piping inside a building, per City of San José Bulletin #276.
Does bathroom plumbing need a vent?
Yes. The vent is what lets the drains flow. In a remodel it goes in with the drain and supply lines while the walls are open.
This kind of job
Sources
- City of San José Bulletin #276, Sewer Installation Requirements (dated 11 June 2019) (checked October 2, 2026)
Water where it should not be?
Call and describe what you are seeing. If it can wait until morning, we will say so.