# Copper Repiping in San Francisco

> Copper repiping in San Francisco: Type L and Type M tube, soldered, brazed and press joints, dielectric transitions, SF water chemistry, testing and permits.

URL: https://hilltoprepipesanfrancisco.com/copper-repiping/

New hot and cold supply in rigid copper tube, joined by solder or press fittings, with dielectric transitions where it meets steel.

Last Updated: October 30, 2026

- **92 of 273** San Francisco repipe permit descriptions from 2021 to 2025 that name copper, more than any other material
- **Type L** Lightest copper tube the California Plumbing Code allows in general; Type M only where 604.3 permits it
- **10% to 60%** Spread of copper's premium over PEX for the same home across sources; reported as a spread, not an average
- **6 inches** Minimum length of a brass nipple between copper and steel under San Francisco's code, if no dielectric fitting is used

A copper repipe replaces a building’s hot and cold supply lines with rigid copper tube, from the main valve to every fixture. [Hilltop Repipe San Francisco](https://hilltoprepipesanfrancisco.com/) offers and manages copper repiping across San Francisco, Daly City and South San Francisco, with the work carried out by licensed and insured contractors under a plumbing permit and city inspection. It can cover the whole building, as on the [whole-house repiping](https://hilltoprepipesanfrancisco.com/whole-house-repiping/) page, or a defined section under [partial repiping](https://hilltoprepipesanfrancisco.com/partial-repiping/).

Copper is still the material most San Francisco repipes are recorded with. Among 273 DBI permit descriptions from 2021 to 2025 that describe a domestic water repipe, 92 name copper, 76 name galvanized steel and 6 name PEX, and the usual pattern is old galvanized coming out and copper going in. Owners who choose copper tend to want a metal system: some because a building or association specifies it, some because they prefer rigid pipe they can see and support, some because it keeps the electrical grounding path continuous. Homeowners report contractors steering them to copper without a convincing reason and quotes for the same house landing far apart, so it helps to know what the material does and does not change.

## What happens on the first visit

The walk-through starts at the meter box and the main valve, with static pressure measured, because San Francisco’s roughly 13 pressure zones make any assumed number unreliable. Then the existing pipe is traced and identified run by run. Many houses already hold some copper from past repairs, and the visit notes whether it is sound or showing green crust and old patch joints.

Copper changes what the route has to allow for. Rigid tube needs a fitting at every change of direction, so the visit looks for straight paths and for places where a joint can be reached with a press tool or a torch and heat shield. It notes every point where new copper will meet steel that stays, such as an old service line or a neighbor’s riser in a shared building, because each needs a dielectric transition. It checks whether the existing metal pipe is part of the grounding path. The written scope then names the tube type, the joining method for each area, the layout, every opening and the permit.

## Type L, Type M and what the code allows

Copper tube comes in wall thicknesses identified by type. The California Plumbing Code makes Type L the minimum for water tube in general, and permits the thinner Type M aboveground in or on a building and underground outside of structures. Type L has the heavier wall, costs more and gives more margin against wear at elbows and high-velocity points. Whatever type is used, the code holds every surface that touches drinking water to 0.25% lead as a weighted average, and solder and flux to 0.2%, so modern copper work does not carry the lead solder of older systems.

Under a slab, the code asks for copper installed without joints where possible, and brazed joints with wrought copper fittings where joints are needed. That rule matters most in a ground-floor garage or an addition on grade; the [partial repiping](https://hilltoprepipesanfrancisco.com/partial-repiping/) page covers rerouting around a slab leak.

## Soldered, brazed and press-connected copper

Most copper above grade is joined with solder or press fittings, and the choice affects the job more than it affects the finished pipe. A soldered joint takes an open flame, a dry line and room to work. In an open basement or garage ceiling that is straightforward. Inside a finished wall of a wood-frame building, next to old framing, lath and painted trim, every torch joint needs heat shields and care, and DBI’s lead-safe guidance for pre-1979 buildings warns against open flames on painted surfaces.

Press fittings carry a sealing ring and are crimped onto the tube with a powered tool. They need no flame, they tolerate a damp line better when tying into old pipe, and they go in quickly in tight cavities. They cost more per fitting. Many copper repipes use both: solder on open runs, press fittings in finished walls and at tie-ins. Brazing, at higher temperature, is used where the code calls for it, such as joints under a slab.

## How copper behaves in San Francisco water

SFPUC water is soft, with average hardness of 62 ppm, and its pH is adjusted to about 9.3 for corrosion control. Water at that pH is less aggressive toward copper than acidic water, and SFPUC’s tap sampling found the 90th percentile copper level at 72 parts per billion against an action level of 1,300. That is a citywide picture, not a promise about any one building.

Copper can still fail, usually as pinholes or leaks at joints, and no single cause explains every case. Flow velocity in undersized lines, workmanship at joints, sediment, electrical conditions and local water chemistry can each play a part. That is why a copper repipe is sized for the fixture load and why joints are made and supported carefully. The [copper pinhole leaks guide](https://hilltoprepipesanfrancisco.com/guide/copper-pinhole-leaks/) covers the causes, and the [guide to San Francisco water and your pipes](https://hilltoprepipesanfrancisco.com/guide/san-francisco-water-and-your-pipes/) covers the chemistry, including the chloramine SFPUC uses as its disinfectant.

## Where copper meets steel

Copper and galvanized steel joined directly form a galvanic couple, and the steel corrodes faster at the joint. San Francisco’s code requires a dielectric or insulating fitting, or a brass nipple at least 6 inches long, wherever copper connects to ferrous pipe. The state code lists the accepted options as a copper-alloy adapter, a copper-alloy nipple of at least 6 inches, a dielectric fitting, or a dielectric union meeting ASSE 1079 or IAPMO PS 66.

These transitions matter most when not everything is replaced. A repipe that leaves an old galvanized service line, connects to a steel gas-fired water heater nipple or meets a shared riser in a flats building has a transition at each of those points. The [galvanized pipe replacement](https://hilltoprepipesanfrancisco.com/galvanized-pipe-replacement/) page explains why leaving steel upstream of new copper is often a false economy, and the [water service line replacement](https://hilltoprepipesanfrancisco.com/water-service-line-replacement/) page covers the owner’s line from the meter box.

## Grounding, insulation and the rest of the system

Because copper conducts, a copper repipe keeps the metal water piping that older houses often used as part of their electrical grounding path. Where the buried building supply serves as a grounding electrode, the California Plumbing Code requires any replacement to be of like material, which copper satisfies. Remaining metal water pipe must still be bonded under the electrical code, and the scope notes where an electrician should confirm it.

Hot lines in an open garage or crawlspace lose heat on the way to the fixtures, and insulating them shortens the wait for hot water; California’s energy code requires insulation on newly installed hot water pipe in some work, such as a water heater replacement. Copper’s rigidity also means water hammer travels well through it, so the air chambers San Francisco requires at single-handle faucets, shower valves and solenoid valves are part of the scope, sized at 24 times the fixture supply diameter.

## Testing, permit and openings

The finished copper system is tested with water at working pressure or above, or with air at 50 psi or more, held for at least 15 minutes without leakage, and the city inspector sees it before walls close. A licensed contractor files the DBI permit on PermitSF: $549 for a house, or $809 with underground work, with a separate permit for each condo or apartment unit and $259 per half hour for any re-inspection. The [San Francisco repiping permit guide](https://hilltoprepipesanfrancisco.com/guide/san-francisco-repiping-permit/) covers the steps.

Copper usually needs more openings than PEX, because the tube cannot bend around obstacles and every turn is a fitting. Where walls are original plaster, those openings are cut and patched with more care, which the [old-house repiping](https://hilltoprepipesanfrancisco.com/old-house-repiping/) page covers.

## What a copper repipe costs

Copper usually costs more than PEX for the same home; sources put the premium anywhere from about 10% to 60%. For reference, a typical San Francisco-area range for a whole-house PEX repipe is $8,500 to $16,000 for one bath, $12,000 to $22,000 for two baths and $14,500 to $28,000 for three, with multi-story or hard-access homes running higher. The extra comes from labor per joint, more fittings and more openings. The [PEX vs copper guide](https://hilltoprepipesanfrancisco.com/guide/pex-vs-copper/) weighs the choice beyond price, and the [repipe cost guide](https://hilltoprepipesanfrancisco.com/guide/repiping-cost/) shows what sits inside a quote.

## What's included

- Static pressure measured at the start, and a pipe map from the main valve to each fixture
- Copper tube of the type named in the scope, Type L unless Type M is allowed and agreed
- Joints by lead-free solder, brazing or press fittings, with the method stated for each area
- Pipe supports, and sleeves or isolation where copper passes through framing or masonry
- Dielectric or insulating fittings at every connection to steel pipe that stays
- Main valve, unit shutoffs and fixture stops the San Francisco code requires
- Air chambers at single-handle faucets, shower valves and other quick-closing valves
- Water heater reconnection with a valve on the cold supply and straps in the upper and lower thirds
- Pressure test, flush, permit and city inspection before walls close

## Soldered or press-connected copper

|  | Soldered joints | Press fittings |
| --- | --- | --- |
| How the joint is made | Tube and fitting cleaned, fluxed, heated and filled with lead-free solder | A fitting with a sealing ring is crimped onto the tube with a powered press tool |
| Heat at the joint | Open flame | None |
| Water in the line | Line must be drained and dry to take solder | Tolerates a damp line better, which helps when tying into old pipe |
| Where it fits | Open runs, new work, any joint with room for a torch and a heat shield | Tight cavities near framing, plaster and finishes; occupied rooms |
| Cost | Lower fitting cost, more labor per joint | Higher fitting cost, faster joints |

## Related resources

- Decision Guide [PEX vs copper for a repipe: which should you choose?](https://hilltoprepipesanfrancisco.com/guide/pex-vs-copper/)Both materials are code-approved in San Francisco. The real differences are in how each one travels through a building, what it costs, how it is joined and what has to change around it.
- Learn [What causes pinhole leaks in copper pipes?](https://hilltoprepipesanfrancisco.com/guide/copper-pinhole-leaks/)There is no single cause. Water chemistry, flow speed, workmanship, sediment and electrical conditions can each thin a copper wall until it opens, and where the leaks appear is the most useful clue to which one is at work.
- Learn [Is San Francisco water hard or soft?](https://hilltoprepipesanfrancisco.com/guide/san-francisco-water-and-your-pipes/)The chemistry of Hetch Hetchy water, read for what it does to pipe: why old steel here clogs with rust rather than scale, what chloramine means for material choice, and why the answer changes a little across the county line.
- 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.
- Learn [Are there lead pipes in San Francisco?](https://hilltoprepipesanfrancisco.com/guide/lead-pipes-san-francisco/)San Francisco's lead story is mostly history and small parts: lead service lines removed decades ago, short lead connectors on old galvanized lines, and household fixtures and solder. What SFPUC reports, and what an owner can check.

## How a repipe runs

1. The call Describe the building Building type, floors, number of baths and units, the pipe you can see in the garage or basement, and what you have noticed.
2. Walk-through Map the pipe The supply is traced from the meter: pipe map, wall types, the main valve, the water heater and where access is easiest.
3. Scope Written scope and price Material, layout, every planned opening, the permit and who patches what, on paper before work is booked.
4. The work Permit, new lines, pressure test The permit is filed, new lines are run while the old ones still serve, fixtures are switched over and the system is pressure tested.
5. Sign-off Inspection, then patching The city inspector signs off with the pipe still visible. Then the openings are closed.

## What this work looks like

Two new copper water lines with press couplings on wall clamps along a San Francisco garage wall

Press-fit copper coupling on a new copper water line hung from a framing member in a San Francisco garage

Brass transition fitting between old galvanized pipe and new copper on a garage ceiling

Strapped water heater on a platform in a San Francisco garage corner with new copper lines and an expansion tank

## Copper repiping questions

### Is Type M copper allowed for a repipe in San Francisco?

Yes, in some places. The California Plumbing Code sets Type L as the minimum for copper water tube, but allows the thinner Type M aboveground in or on a building and underground outside structures. Some owners specify Type L throughout anyway. The scope should name the type for each part of the job.

### What is the difference between press-fit and soldered copper?

A soldered joint is heated with a torch and filled with lead-free solder. A press joint uses a fitting with a built-in sealing ring that a powered tool crimps onto the tube, with no flame. Both are code-approved ways to join copper. Press fittings cost more each but go in faster and avoid open flame inside finished, occupied rooms.

### Is copper the right choice for every San Francisco repipe?

No material is. Copper suits owners who want a rigid metal system, buildings that specify it and houses where the metal supply pipe carries the electrical ground. PEX usually needs fewer openings and costs less. Both are approved by the California Plumbing Code, and San Francisco restricts neither, so the choice comes down to the building, the route and the owner's priorities.

### Can new copper be joined to galvanized pipe that stays?

Yes, with the right fitting. San Francisco's code requires a dielectric or insulating fitting, or a brass nipple at least 6 inches long, wherever copper connects to steel. Joining them directly sets up galvanic corrosion that eats the steel at the joint. The scope should list each transition so none is missed.

### Why do copper repipe quotes for the same house differ so much?

Because they often describe different jobs. Type L or Type M tube, soldered or press joints, the number of openings, whether patching is included and which valves and transitions are listed all move the total. Homeowners report copper quotes for the same house landing thousands apart. Sources put copper's premium over PEX anywhere from about 10% to 60%, a spread rather than an average.

## Related services

### Whole-house repiping

Every hot and cold supply line from the main valve to each fixture, in PEX or copper, tested and inspected.

Whole-house repiping

### PEX repiping

New hot and cold supply in crosslinked polyethylene tubing, routed through joists and chases with fewer openings, tested and inspected.

PEX repiping

### Galvanized pipe replacement

Old threaded steel supply pipe replaced with PEX or copper, with listed transitions, a flush for loosened rust and a city inspection.

Galvanized pipe replacement