Water heater dying. A drain that won’t clear. A stain spreading across the ceiling of the flat below yours.
Send a few details and one vetted, licensed San Francisco plumber gets back to you. Not five companies fighting over your phone number. Tell us what’s happening, when it started, and roughly how old the building is; those three things get you a much sharper first read than a form full of dropdowns ever will.
Your building’s age is the whole story
Roughly two-thirds of San Francisco’s housing went up before 1940. Victorians and Edwardians through the Mission and Noe Valley. The long rows of Richmond and Sunset flats from the 1930s and 40s. Post-quake rebuild stock south of Market. Much of it still carries the pipe it was born with.
That means galvanized steel on the supply side and cast iron on the drains. Both corrode from the inside out. Both were built for a 50-year life and are decades past it.
How to tell, in about ten minutes, without paying anyone
Find where the water line enters the building, usually in the garage or under the front stairs, and run a refrigerator magnet down it. If it sticks, that’s steel. Copper and brass won’t hold it. Then run a long-unused tap: water the colour of weak tea is galvanized shedding its lining.
The drain side is quieter and considerably worse. Cast-iron stacks rust through at the base, inside a wall, and announce themselves when the plaster gives.
You almost certainly do not need a water softener here
San Francisco drinks Hetch Hetchy snowmelt. It arrives at roughly 1 to 3 grains per gallon, among the softest municipal supply in California, and a fraction of the 17 to 19 grains San Diego pushes through its pipes.
If a company quotes you a softener, ask what hardness reading they took. The scale that eats water heaters in Sacramento is not what is killing yours. Age and sediment are.
Soft water does have one quiet downside: it is mildly aggressive toward copper. So the pinhole leak in a 1960s copper line is a familiar call, and it usually shows up as a rust-coloured freckle on a pipe in the garage long before it shows up as water anywhere.
The lateral is yours, and it is probably deep
Below the sidewalk the city runs a combined sewer: storm water and sewage share a pipe. You own the side sewer, the lateral from your building out to the main. On a hillside lot in Bernal or up toward Twin Peaks that run can be 60 feet and sit deep.
Which is why the camera is the cheapest money in the entire job. Around $300 answers the only question that matters: reline it, spot-repair it, or open the sidewalk. Skipping it to save the $300 is how people pay for a dig they never needed.
- Being quoted a full sewer line repair with no camera? Get a second opinion.
- Lowest fixture a basement floor drain or a garage-level toilet? Ask about a backwater valve. A main-line surcharge in a December storm has to come out somewhere, and it finds the lowest opening in the building. That is not a job for a snake.
- Roots. Eighty-year-old street trees, original clay, nowhere else to go.
What density does to the bill
Three units stacked on a 25-foot lot. A stack that fails at the base is not one household’s problem, it is a downstairs neighbour’s ceiling. There is no driveway to stage from, the cleanout is behind a wall someone finished in 1994, and access drives the price more than the plumbing does.
Rough 2026 figures, to orient a conversation rather than quote one:
| Job | Typical SF range | What actually moves it |
|---|---|---|
| Tank water heater replacement | $2,200–$4,500 | Closet access; seismic strapping; venting |
| Tankless conversion | $5,500–$10,000 | The gas and venting upgrades it forces |
| Drain cleaning | $200–$600 | How buried the cleanout is |
| Spot repair, sewer lateral | $4,000–$9,000 | Depth, and whether the sidewalk opens |
| Full side-sewer replacement | $10,000–$30,000 | Hillside depth, permits, sidewalk restoration |
| Whole-home repipe out of galvanized | $10,000–$20,000 | Wall access, unit count, finish repair |
Water heaters are the second-biggest bucket after drains. Emergency calls are third, and they cluster in the pre-war flats, on the night the galvanized finally lets go.
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Things people actually ask
Is San Francisco water hard?
No. About 1 to 3 grains per gallon. Save your money.
Whose problem is the sewer lateral?
Yours. The property owner owns and maintains the side sewer all the way out to the city’s combined main, and on a steep lot that is a long, deep run. Roots in old clay and cracked cast iron are the two failures you see over and over. Camera first, always: it settles spot-repair versus liner versus dig before anyone picks up a shovel, and it is the difference between a $5,000 job and a $25,000 one.
Do I need a permit?
For anything past a like-for-like repair, yes. Permits come from the San Francisco Department of Building Inspection, side-sewer work is coordinated with the SFPUC, and a water heater swap has to land on current seismic strapping (and often venting and gas) to pass inspection.
A licensed C-36 plumber pulls the permit and carries the inspection as part of the job. You can verify any licence number yourself on the CSLB site in under a minute, and it is worth the minute. Unpermitted work has a habit of surfacing at the worst possible moment: during a sale, in front of a buyer’s inspector, with money on the table.
My downstairs neighbour has a stain on the ceiling. Is that on me?
Maybe, and here is the annoying part: in a stacked flat, water travels. The stain is where it exits, not where it started. A leak at your shower pan can surface eight feet away. Tracing it beats guessing, and guessing is what leads to an opened ceiling in the wrong room.
Send your San Francisco plumbing details
Most calls that come through here turn out to be a repair, not a replacement. A worn valve. A rooted lateral. One tired section of galvanized behind the kitchen.
Describe what you’re seeing and you’ll get an honest read on scope and cost, with nobody pushing you to book. No cost, no obligation, and a straight answer from the one vetted, licensed San Francisco plumber who’d do the work.