Rough plumbing is the floor, not the total
Rough plumbing is pipes, drains, and vents. Tile, fixtures, an exhaust fan, and lighting are separate lines. This site does not publish a rough-plumbing or finish-tier table. The published plumbing band for a full ADU kitchen, bath, and water heater is $12,000-$30,000 on the plumbing service page. That is a whole-job market range, not a tile quote.
Tile
Tile is usually the largest finish variable: shower surround, floor tile, and whether the shower is a simple surround or a curbless walk-in. The licensed tile setter prices pattern, waterproofing, and square footage from the drawings. This site does not publish those line items.
Fixtures
Toilet, sink, faucet, and shower valve scale with quality. Compare fixtures as named models on the bid, not as a spoken “standard package.”
Ventilation
Every ADU bathroom needs a working exhaust fan. In a garage conversion the duct often has to go through a roof or wall that was not built for it. The plumber or electrician prices that penetration from the plans.
Putting the full picture together
Finish work sits on top of rough plumbing. Compare a complete bathroom scope, not a plumbing-only number you found online.
Lighting, paint, and hardware
A finished bathroom needs vanity lighting, a GFCI outlet, an exhaust-fan switch, moisture-resistant paint, trim, a mirror, and hardware. Put those on the bid as named lines. This site does not invent a hardware add-on total.
Where San Diego specifics change the number
Hard water is a real factor in fixture selection here. Shower valves, faucets, and glass shower doors all show mineral buildup faster in San Diego’s hard water than they would in a soft-water region, and cheaper fixtures tend to show it sooner and more visibly. Spending a bit more on a quality shower valve and considering a glass coating treatment on shower doors is a reasonable place to upgrade if the budget allows, since it affects how the bathroom looks in year three, not just on move-in day.
Why is my bathroom quote so much higher than the rough plumbing estimate I saw online?
Rough plumbing is pipes and drains. Tile, fixtures, ventilation, and lighting are separate. Compare a complete bathroom scope, not a plumbing-only number.
What’s the cheapest way to finish an ADU bathroom without it looking cheap?
Standard ceramic tile in a straightforward layout, a quality mid-tier toilet and faucet set rather than the absolute lowest-cost option, and a simple three-wall shower surround instead of a curbless design keep costs down while still looking finished and durable.
Can I phase the bathroom finish to spread out the cost?
Some homeowners rough in the plumbing and install basic, code-compliant fixtures and tile at move-in, then upgrade to higher-end finishes later once the ADU is generating rental income or the budget allows. This works structurally as long as the initial fixtures are genuinely functional and code-compliant, not a placeholder that will need to be torn out rather than simply swapped for a nicer version later on.
Do I need a permit for bathroom finish work in an ADU?
The rough plumbing and any new electrical for the bathroom require permits as part of the overall ADU conversion permit. Finish-level work like tile and fixture installation is typically covered under that same permit rather than needing a separate one, but confirm the specific scope with your contractor and San Diego Development Services.
For a detailed bathroom finish estimate based on your specific ADU layout, see our plumbing for ADU page or call (858) 400-4935.
Garage Convert SD connects San Diego homeowners with experienced, insured crews for full ADU conversions. Call (858) 400-4935 to get matched with a crew that does this work.