A Victorian in Pacific Heights and an Edwardian in Noe Valley have the same secret. Behind the plaster, in the redwood framing, runs a water system nobody has looked at since it was installed, patched by a dozen hands over a century, and now near the end of what steel pipe can do.
Repiping one of these houses is not difficult plumbing. It is careful plumbing. The pipe work is a known quantity to anyone who has done it for a few decades. The skill is getting new lines to every fixture in a three story house without destroying the plaster runs, the millwork, and the original finishes that are the reason anyone wants the house.
Here is how to tell where your system is in its life, what the choices behind the wall come down to, and what a repipe planned properly looks like from the first walk-through.
Signs the system is finished
Rusty water at first draw is the famous one, and it is a late signal rather than an early one. The earlier signs are quieter.
Pressure that fell off slowly. Galvanized steel corrodes from the inside. The scale builds inward until the effective bore of a half inch line is the diameter of a pencil. Owners rarely notice, because it happened over fifteen years. The tell is comparative: the shower drops noticeably when someone runs a tap two floors down, or the top floor never recovered after a bathroom was added.
Hot side worse than cold. Heat accelerates the corrosion, so in most old houses the hot lines fail first. If your hot pressure is visibly weaker than your cold at the same fixture, the pipe is telling you where it is in its life.
Repeat pinholes. One pinhole leak is an event. Three in two years is a system. Steel does not fail in one place, it fails everywhere at once, and the second and third leaks are the ones that arrive while you are away.
Discoloration after a period away. Water that sat in the pipe over a weekend comes out tinted. That color is the inside of your pipe.
Fittings that will not take a repair. The point where a plumber cannot cut and thread into the existing line without the adjacent section crumbling is the point where patching has stopped being economical.
The published service lives are a useful frame. Copper runs fifty to eighty years, galvanized steel twenty to forty, plastics twenty to fifty and longer. A house built in 1905 and plumbed in galvanized is on its second or third system by now, and whatever is in there was probably installed in an era when nobody expected it to still be there.
What is behind the plaster
Open a wall in a San Francisco pre-war house and you rarely find one system. You find an archaeology.
There is usually original galvanized steel, threaded, running vertically in the stud bays. There is often original brass, especially in the earliest work, which is a better material than the steel that replaced it and is sometimes still serviceable. There is copper from a mid century remodel, joined to the steel with a fitting that has been quietly corroding since the day it was made, because dissimilar metals in contact with water do that. There is flexible supply from a 1990s bathroom. There may be a section of galvanized that someone sleeved rather than replaced.
Alongside all of it there is knob and tube wiring, which is not our trade, but which shares the same cavities and dictates where we can and cannot work without an electrician present.
None of that is a problem. It is the reason a repipe in one of these houses is bid after somebody has been inside the walls, not from a floor plan.
Copper and PEX: the honest version
The debate is usually presented as a loyalty test. It is a materials decision, and both materials earn their place in a historic house.
Copper is rigid, it is proven for fifty to eighty years, it tolerates high temperature, it does not care about sunlight, and it can be run tight and clean in an exposed mechanical room where it will be looked at. It also needs more openings: rigid pipe has to be threaded through framing in straight runs with fittings at every turn, and every fitting is a joint and an access requirement.
PEX is flexible, which in a lath and plaster house is the whole argument. A flexible line can often be pulled through an existing cavity, around a corner, and up a bay from below with one opening instead of five. Fewer openings is less plaster, less paint, less millwork disturbed, and a shorter job. It also handles the small seismic movement these houses make better than a rigid system with a hundred rigid joints.
In practice we mix them, and we are not unusual in that. Copper for the mechanical room, the manifolds, the exposed work and the high heat runs. PEX for the concealed distribution through finished floors where the alternative is opening a hallway ceiling that has been intact since 1912.
Anyone who tells you one material is correct in every house is describing their own preference, not your building.
Protecting the house while you work in it
This is the part that separates a repipe in a historic home from a repipe in a tract house, and it is decided before the first cut.
We start with a route. Every fixture is mapped, then the path to it is chosen for the least damage rather than the shortest distance: through closets, through the backs of cabinets, up the chase a previous plumber already made, from the crawl space and the attic rather than through the middle of a decorated wall. On most floors the number of openings can be brought down substantially just by thinking about it for an afternoon before anyone picks up a saw.
Then containment. Lath and plaster does not cut like drywall. It shatters, it delaminates from the lath, and it makes a dust that gets into everything. Cuts get scored, plastic goes up, floors get covered, and the work area is kept closed off from the rest of the house.
Then restoration. An opening in plaster gets patched as plaster, not filled with a sheet of gypsum and a smile. Millwork that has to come off gets labeled and comes off whole. Where a finish cannot be matched, the right answer is to route around it rather than promise a repair nobody can make.
The test we use is simple. A month after the work, someone who lives in the house should have to be shown where we were.
What the work involves
A whole house repipe on a typical three story San Francisco home runs in a fixed order.
- Walk-through and map. Fixture count, pipe material, access, and the route. This is also where we find the things nobody mentioned, like the bathroom addition fed off a line that was never sized for it.
- Permits. Repiping is permitted work, and it is inspected.
- Open only what the route needs. Openings are cut to size and located deliberately.
- Run the new distribution, sized properly rather than copied from what was there, because what was there was sized for a house with one bathroom.
- Tie in, section by section, so water is off for planned hours rather than for days. On an occupied house we keep at least one bathroom live at the end of each day.
- Pressure test and inspection.
- Close up and restore.
Occupied houses take longer than empty ones, and that is the correct trade. An owner who can move out for the duration gets a faster and slightly cheaper job.
What drives the number
We do not publish a repipe price, and any firm that quotes one over the phone for a house like this is quoting a different house.
What moves it: the number of fixtures and their spread across floors, whether the house has a crawl space and an attic to work from, wall construction and finish quality, how much of the existing route can be reused, whether the water service from the meter is being replaced at the same time, and how much restoration is in our scope rather than a painter's.
How we handle it: we prefer to walk the property before bidding. A proposal written without a site visit is a budgeting number and we say so. Written proposals take about seven business days, or ten when fixture pricing is part of the request. That is slower than a same day quote off a photograph, and it is the reason our numbers hold.
During a remodel, or on its own
If the house is already scheduled for work, repipe then. Walls that are open for a kitchen or a bath are walls we do not have to open twice, and the marginal cost of the repipe against an already open house is a fraction of the standalone job.
This is the single best argument for planning the mechanical scope early in a whole home renovation rather than treating plumbing as a trade that shows up after the drawings are done. The same visit is the moment to look at the water service, the drain lines, and whether the sewer lateral is going to be a permit condition anyway.
As a standalone project it still makes sense when the leaks have started. The arithmetic is not the price of the repipe against zero. It is the price of the repipe against a decade of emergency calls, plaster repairs, and one failure while nobody was home. Water damage is the expensive part of a pipe failure, and it lands on the finishes rather than on the plumbing.
Questions to ask before anyone opens a wall
- Where exactly will the openings be, and why there?
- What material where, and what is the reason for each?
- Who patches the plaster, and is that in this number?
- How long is the water off each day, and which bathroom stays live?
- Are permits and inspections in the scope?
- Have you repiped a house of this age and construction, and where?
- What happens if you find something behind the wall that changes the scope?
The last one matters most. In a house this old, something will be found. What you are buying is how the firm behaves in that moment.
Where we come into it
We have been repiping and repairing water lines in these houses since 1998, under CSLB license #746000, with twenty licensed, bonded and insured plumbers. Old San Francisco housing stock is the majority of what we work in, and the discipline of working inside a finished home is the part we were trained on rather than the part we added later.
After a repipe, the system is worth keeping an eye on: pressure, the water heater, the shutoffs, the fixtures. That is what our home protection plans do, and it is also how a small leak somewhere new gets caught by leak detection before it reaches a ceiling.
If the pressure has been falling for years, or the third pinhole just arrived, request an assessment and we will come and look at the house before we say anything about the number.
