# An Illustrative Whole-House Repipe Walkthrough in San Francisco > An illustrative walkthrough of a typical San Francisco whole-house repipe: first call, pipe map, written scope, permit, pressure test, inspection and patching. URL: https://hilltoprepipesanfrancisco.com/blog/whole-house-repipe-walkthrough/ Illustrative Walkthrough An illustrative walkthrough, not the record of a real job: what a typical whole-house repipe of a two-bath San Francisco house involves at each step, and why each step is there. Last Updated: October 30, 2026 > An illustrative walkthrough > > This post describes what a typical job looks like from start to finish. It is not the record of a specific completed project. This is an illustrative walkthrough. The house below is a composite drawn from the San Francisco housing, code and permit facts used across this site, not a specific job, customer or address. [Hilltop Repipe San Francisco](https://hilltoprepipesanfrancisco.com/) offers and manages [whole-house repiping](https://hilltoprepipesanfrancisco.com/whole-house-repiping/) in San Francisco, Daly City and South San Francisco, with the work carried out by licensed and insured contractors, and this post follows the steps that work goes through, in order, with the reason for each. ## The house in this example Picture a two-bath house from the 1930s with its living floor over a ground-floor garage, the layout San Francisco Planning describes as characteristic of the [Sunset](https://hilltoprepipesanfrancisco.com/service-areas/sunset-parkside/). Its galvanized mains run along the garage ceiling. A later remodel put the upstairs bathroom on copper, so copper and steel meet somewhere overhead. The owners have noticed brown water after a weekend away and weak flow at the upstairs shower when someone runs the kitchen tap. Nothing in that description proves the pipe is the problem. Brown water and low flow fit galvanized pipe rusting from the inside, which is how it fails in San Francisco’s soft water, but a partly closed valve, a failing pressure regulator or the service line can produce the same symptoms, as the [low water pressure guide](https://hilltoprepipesanfrancisco.com/guide/low-water-pressure/) explains. That is why the next step is a look, not a price. ## The call The first call collects what the owners can see: the year the house was built, the number of bathrooms, whether the garage ceiling is open, where the water heater sits, what the pipe looks like where it shows, and what they have noticed. It is also when they say whether the house is occupied during the work and whether any other project, such as a kitchen remodel, is planned. Each of those changes the route or the schedule. ## The walk-through The walk-through starts where the water comes in: the meter box at the sidewalk and the main valve, where static pressure is measured. San Francisco has about 13 pressure zones fed from reservoirs and tanks at different heights, so pressure is read at the house, not assumed. Then the pipe is traced from the main along the garage ceiling, up each riser and out to every fixture. That trace becomes a pipe map showing what is galvanized, what is copper and where the two meet. The walk-through also records the walls each new line will pass through, plaster or drywall, and whether any are tiled, because that decides how openings are cut and patched. In a house built before 1979, painted surfaces are presumed to contain lead under San Francisco’s rules, so lead-safe practices are planned in. The water heater is checked for its valves, its connections and its seismic straps, which state law requires on existing residential heaters as well as new ones. The [guide to how invasive repiping is](https://hilltoprepipesanfrancisco.com/guide/how-invasive-is-repiping/) shows the kind of openings involved. ## The written scope and price The written scope turns the pipe map into a plan. It names the material, PEX or copper, both of which the California Plumbing Code lists for water distribution; the route; each opening and who patches it; the valves the code adds; and the permit. For a two-bath house like this one, the typical San Francisco-area range for a whole-house PEX repipe is about $12,000 to $22,000, with copper usually higher and multi-story or hard-access homes able to run above the range. Where this example’s house lands depends on the garage ceiling being open, the plaster upstairs and the number of fixtures. The [repipe cost guide](https://hilltoprepipesanfrancisco.com/guide/repiping-cost/) explains each driver. The scope also says what is not included. A whole-house repipe replaces the hot and cold supply pipe; the drains and the buried line from the meter are separate unless the scope adds them. In this example, the owner-side service line is old galvanized meeting new utility copper at the sidewalk, so the scope prices its replacement as an option. [Water service line replacement](https://hilltoprepipesanfrancisco.com/water-service-line-replacement/) covers that run. ## The permit Once the owners approve the scope, the licensed contractor files the plumbing permit on PermitSF, San Francisco’s online permit system. DBI requires a permit before cutting into or replacing pipe that will be covered by a wall or buried. For a house, DBI’s fee is $549, or $809 when underground work such as the service line is included, and any re-inspection is $259 per half hour. The [San Francisco repiping permit guide](https://hilltoprepipesanfrancisco.com/guide/san-francisco-repiping-permit/) covers filing and inspections. ## Running the new lines The new system goes in alongside the old one. In this house, the trunk is built along the open garage ceiling first, with a fullway valve where the supply enters and a valve on the water heater’s cold supply. Branches then come up through the floor to each fixture group, and each fixture gets its own control valve, as San Francisco’s code requires. Single-handle faucets and shower valves get air chambers to absorb water hammer. Where any galvanized or steel pipe stays connected, a dielectric or insulating fitting goes at each copper-to-steel joint. Water goes off in stages, as each fixture group is switched to the new lines, rather than for the whole job. When metal pipe that carried an electrical bond comes out, the scope notes it so an electrician can confirm the bonding. The [guide to how long repiping takes](https://hilltoprepipesanfrancisco.com/guide/how-long-does-repiping-take/) covers the schedule. ## The pressure test and the inspection Before anything is covered, the new system is pressure tested. The California Plumbing Code calls for a test with water at or above working pressure, or with air at a minimum of 50 psi, held for at least 15 minutes without leakage; plastic pipe is air-tested only where its manufacturer permits, which some PEX systems do. If static pressure at the meter is above 80 psi, the code adds a pressure regulator and an expansion tank. Then the city inspector sees the exposed work. Walls close only after the inspection passes. ## Patching the openings The last step is the one owners notice most. Each opening on the scope’s list is closed and patched by whoever the scope names for it, and lead-safe clean-up follows wherever painted surfaces were disturbed. In this example, the upstairs openings are limited to where the lines climb behind the kitchen sink, the bathroom group and the laundry, because the garage ceiling carried the trunk. ## What changes in a different building Change one fact and the walkthrough changes with it. In a building of flats, each unit needs its own shutoff under San Francisco code and its own permit, and occupied units shape the schedule. In a finished garage, the ceiling is opened like any other. In South San Francisco, hard groundwater adds mineral scale to the diagnosis. The [cornerstone guide to how repiping works](https://hilltoprepipesanfrancisco.com/guide/repiping-guide/) covers all of it in one place, and [galvanized pipe replacement](https://hilltoprepipesanfrancisco.com/galvanized-pipe-replacement/) covers the most common starting point. ## Questions about this post ### Is the house in this repipe walkthrough a real job? No. It is an illustrative composite built from the San Francisco code, permit and housing facts this site relies on, so it shows what a typical job involves without describing any particular customer or address. A real scope comes from a walk-through of your own house. ### Why does a San Francisco repipe add valves the old system never had? Because the city's plumbing code asks for them. San Francisco's amendments require a fullway valve where the supply enters, a valve on the water heater's cold supply, a control valve at each fixture and air chambers at quick-closing valves such as single-handle faucets, so a repipe brings an older house up to those rules. ### When is the pressure test done during a repipe? After the new lines are run and before any wall closes. The California Plumbing Code calls for the system to hold water at or above working pressure, or air at 50 psi, for at least 15 minutes without leaking; PEX is air-tested only where its manufacturer allows. The city inspector then sees the exposed work. ## Keep reading - Learn [How does repiping a house work?](https://hilltoprepipesanfrancisco.com/guide/repiping-guide/)The whole picture in one place: what the water supply system is, what San Francisco buildings were piped with and why it fails here, how a repipe is scoped, permitted, installed, tested and lived through, and what to ask before agreeing to one. - Learn [How invasive is repiping a house?](https://hilltoprepipesanfrancisco.com/guide/how-invasive-is-repiping/)A repipe opens walls in planned places, not along every pipe. Where the old lines run, what the walls are made of and how the building is stacked decide how many openings there are and how much patching follows. - Learn [How long does it take to repipe a house?](https://hilltoprepipesanfrancisco.com/guide/how-long-does-repiping-take/)A repipe runs in stages: scope, permit, new lines, cut-over, test, inspection, patching. The pipe work is only one of them, and the building decides how long each one takes. - Learn [Do you need a permit to repipe a house in San Francisco?](https://hilltoprepipesanfrancisco.com/guide/san-francisco-repiping-permit/)Yes, and the permit shapes the job: who files it, which fee category applies, when the inspector comes and what the inspector looks for before a single wall is closed. - Cost Guide [How much does it cost to repipe a house in San Francisco?](https://hilltoprepipesanfrancisco.com/guide/repiping-cost/)Typical San Francisco-area ranges for a whole-house repipe by number of baths, what sits inside the price, the permit fees by city, the programs that help and why two quotes for the same house can differ.