Category: Plumbing

A whole-house repipe replaces every hot and cold water line inside your home, from where the water enters the house to the shutoff at each fixture, in one planned job. In Los Angeles it is usually the right call when the house still has galvanized steel supply pipe, or when copper has started leaking in more than one place: galvanized pipe corrodes shut from the inside and cannot be restored, and a second pinhole in old copper is rarely the last. PEX and copper are both approved under the California Plumbing Code. The plumbing typically takes 2 to 5 days plus drywall patching, works through openings at fixture walls rather than gutted rooms, and needs a permit and an inspection before the walls close. Drains are a separate question.

We are Green Design and Build, a licensed residential general contractor based in Van Nuys (CSLB #1110975), working across Los Angeles, Orange and Ventura counties and the western parts of Riverside and San Bernardino counties. We plan and manage repipes, including the wall openings, patching and paint, often as part of a remodel; the plumbing itself is performed by licensed C-36 plumbing contractors we schedule and supervise. This guide has no prices in it on purpose. A repipe is priced from the house, and that number comes from a site visit.

What a whole-house repipe replaces, and what it does not

“Repipe” means the water supply system. It does not automatically include the drains, the sewer line or the gas piping, and many disputes start with that assumption.

System	What it carries	Common older materials	Part of a repipe?
Water service	Cold water from the utility meter to the house	Galvanized steel, copper	Sometimes. Often quoted separately
Water distribution	Hot and cold water to every fixture and appliance	Galvanized steel, copper	Yes. This is the repipe
Shutoffs and supply lines	Connections at sinks, toilets, washer box, water heater	Old multi-turn valves, chrome supplies	Should be. Confirm in writing
Drain, waste and vent	Wastewater from fixtures to the building drain	Cast iron, some galvanized and ABS	No. A separate scope
Sewer lateral	Wastewater from the house to the city main	Clay, cast iron, Orangeburg	No. See our sewer line replacement guide

Have the scope say in plain words whether it includes the line from the meter, every hose bibb, the water heater connections, the washer box, the ice-maker line, new shutoff valves at every fixture and the patching afterwards. Those are the usual change orders.

Galvanized pipes: why they fail and how to tell if you have them

Galvanized pipe is steel coated in zinc to slow rust. Over decades the zinc wears through and the steel corrodes from the inside. Rust and scale narrow the bore and pressure drops, usually first on the hot side and at the fixtures farthest from the meter. Leaks tend to start at the threads, because cutting a thread removes part of the pipe wall.

Galvanized steel is still listed as an approved material in Table 604.1 of the 2025 California Plumbing Code, so nothing forces you to remove a working system. People replace it because of its condition. Descaling the inside of a galvanized system in an occupied house is not a realistic fix.

How to check what your pipes are made of

• Look where pipe is exposed: under sinks, at the water heater, at hose bibbs and, on a raised foundation, in the crawl space.
• Use a magnet. It sticks to galvanized steel, not to copper or brass.
• Look at the joints. Galvanized is dull gray with threaded fittings; copper is reddish-brown with soldered or pressed joints; PEX is flexible red, blue or white tubing.
• Expect a mix. Many older houses were partly repiped over the years. A mixed system keeps all the problems of its galvanized part.

Where copper meets galvanized, look at the joint. The California Plumbing Code (Section 605.15, as adopted for housing) requires dielectric unions wherever dissimilar metals connect. Without one, the joint corrodes faster, which is one reason piecemeal repairs in older houses often lead to more leaks.

Old copper: pinholes, green stains and lead solder

Copper lasts well, but not forever. Warning signs are pinhole leaks (a damp spot in drywall or a fine spray under a sink), blue-green deposits on pipes and fittings, and repeat leaks in different places. One leak at a fitting is a repair. A second or third pinhole in straight pipe usually means the wall is thinning throughout.

Wall thickness matters. CPC Section 604.3 requires at least Type L copper for water piping, with an exception allowing thinner Type M above ground inside a building or underground outside it. A repipe is a chance to choose the heavier wall deliberately.

There is also a health reason to look at older copper. The EPA’s guidance on lead in drinking water notes that lead pipes are more likely in homes built before 1986, and that in homes without a lead service line the most common problem is brass faucets and plumbing with lead solder. Current code (CPC 604.2) limits solder and flux to 0.2 percent lead. If your system predates that and you are concerned, a test from a certified laboratory tells you more than a visual check.

Cast-iron drains: a separate decision

Many older Los Angeles houses have cast-iron drain and vent piping. It fails differently from supply pipe: it scales inside, and horizontal runs can crack along the bottom where water sits. Signs are slow drains in several fixtures at once, gurgling, sewer odor indoors, or rust stains on a ceiling below a bathroom.

The way to know is a camera inspection. Some cast-iron systems have years left; others need sections replaced. The code lists cast iron, ABS and PVC as approved drain materials (CPC Table 701.2), and replacement is usually ABS or PVC. Drains under a slab are a much bigger job than drains in a crawl space. If you see slab cracking near plumbing, read our guide to which foundation cracks matter; leaking drains and foundation movement can each cause the other.

Warning signs that point to a repipe

One sign alone proves little. Two or three together, in a house with galvanized or aging copper supply lines, usually do.

• Brown or rusty water when a tap is first opened
• Low pressure at several fixtures, not just one
• A shower that swings hot or cold when another fixture runs
• A second leak within a year or two, somewhere new
• Pinholes in straight runs of copper
• Visible rust, scale or green corrosion on exposed pipe
• Any galvanized supply pipe still in service
• A remodel that will open the walls anyway

Symptoms that are probably not the pipes

Symptom	More likely cause	Check first	Repipe likely?
Low pressure at one faucet	Clogged aerator or worn cartridge	Clean the aerator	No
Sudden low pressure everywhere	Failing pressure regulator or utility issue	The regulator; the water utility	Not usually
Rusty water from hot taps only	Corroding water heater tank	Drain a little from the heater	Possibly not
Rusty water hot and cold	Corroded galvanized supply pipe	Identify the pipe material	Likely
Slow drains in several fixtures	Drain or sewer problem	Camera inspection	No

Pressure matters too. If static pressure is above 80 psi, CPC Section 608.2 requires a regulator that brings it to 80 psi or less, and high pressure shortens the life of every pipe and valve. Where a check valve, backflow preventer or other normally closed device keeps pressure from bleeding back into the main, CPC 608.3 requires an expansion tank or similar device. A good repipe scope includes a pressure reading.

PEX vs. copper for a repipe

Both are approved, both must be certified for drinking water, and either lasts for decades when installed properly. In an existing house, PEX is the usual choice for concealed runs: flexible tubing pulls through walls and ceilings with fewer, smaller openings and far fewer joints. Copper suits exposed pipe, short straight runs and owners who want metal throughout. Our remodel plumbing service typically specifies PEX for concealed work and copper where pipe is exposed or the owner prefers it.

Factor	PEX	Copper
Code status	Listed in CPC Table 604.1	Listed in CPC Table 604.1
Drinking-water standard	NSF/ANSI/CAN 61 (CPC 604.1)	NSF/ANSI/CAN 61 (CPC 604.1)
Form	Flexible coils; bends around obstacles	Rigid lengths; a fitting at most turns
Joints	Crimp, clamp, expansion or press, per the manufacturer (CPC 605.9)	Lead-free solder or press fittings
Wall openings	Usually fewer and smaller	Usually more, with room to make each joint
Sunlight	California requires at least 30-day UV protection (CPC 605.9); run concealed	Tolerates exposure
Pressure test	Water; air only if the manufacturer allows (CPC 609.4)	Water, or air at 50 psi minimum
Water chemistry	Tubing does not corrode; brass fittings must resist dezincification where required	Can pinhole in some water conditions
Labor and material	Usually lower	Usually higher

Under CPC 604.1, every pipe, fitting, solder and flux in a drinking-water system must comply with NSF/ANSI/CAN 61, the standard for contaminants that system components can add to drinking water. Look for the mark on the tubing and fittings.

Manifold or trunk-and-branch

PEX can run as a home-run system, with a separate line from a central manifold to each fixture, or as trunk-and-branch, with a larger main and branches like a traditional copper layout. Home runs let you shut off one fixture at the manifold; trunk-and-branch uses less tubing. The right choice depends on where the water heater sits and how far the farthest bathroom is.

PEX-A, PEX-B and fittings

PEX-A is commonly joined with expansion fittings, PEX-B with crimp or clamp rings. What matters most is a matched, listed system installed exactly as its manufacturer requires, by someone trained on it. Mixing brands and fitting types is a common cause of leaking joints.

What happens during a repipe, step by step

1. Site visit and scope. Identify existing materials, map fixtures, read the static pressure, check the main shutoff and decide the route: crawl space, attic or both.
2. Permit. Pulled before work starts. In the City of Los Angeles, that is an LADBS plumbing permit.
3. Protection. Floors are covered, furniture is moved off the walls being opened, and dust barriers go up.
4. Access openings. Small openings at each fixture wall: behind toilets, at sinks, at the tub and shower valve, the washer box and the water heater.
5. New pipe. Lines are run, secured and connected with new shutoff valves. Reachable old pipe is removed; pipe buried in walls is usually cut and left in place, carrying no water.
6. Test and rough inspection. The system is pressure-tested and inspected while the walls are still open.
7. Patching. Openings are closed, taped, textured and readied for paint.
8. Final inspection. The permit is finaled; older houses may also need fixture upgrades (see permits below).

Raised foundation vs. slab

Foundation type shapes the whole job. On a raised foundation, new lines run through the crawl space and come up into each wall from below, keeping openings small. On a slab, supply lines usually cannot go under the floor without breaking concrete, so the system is routed through the attic and dropped down the walls, which means more ceiling work and attention to insulation in the attic. Two-story houses add vertical runs, often through closets or chases. Those factors, plus the number of bathrooms, plaster walls, tile and any water heater work, decide whether a job lands at the short or long end of the 2-to-5-day range our plumbing page publishes.

Wall openings, plaster and patching

Patching is where repipes earn their reputation, good or bad. Put it in the contract.

• Drywall is simplest: cut clean, patched, textured to match, primed.
• Plaster and lath, common in older Los Angeles houses, is harder to cut neatly and to blend.
• Tile walls are best reached from the back, through a closet or the next room, so tile is not broken. Plan that before anyone cuts.
• Exterior stucco is opened at hose bibbs. A poorly built patch lets water in; our stucco repair guide explains how patches should be done.
• Paint is often excluded from a plumber’s quote. Ask who matches the color.

As a general contractor, we keep plumbing, patching and paint in one scope with one schedule, rather than leaving you to hire a separate drywall crew.

What drives the cost of a repipe

We do not publish repipe prices because two houses of the same size can need very different jobs. These factors move the number:

• Fixtures and bathrooms. Every sink, toilet, tub, shower, hose bibb and appliance connection is a run of pipe, a valve and an opening.
• Stories. A second floor adds vertical runs and openings.
• Foundation and access. A clear crawl space is easiest; a slab with a tight attic is hardest.
• Material. PEX generally costs less to buy and install than copper.
• Finishes. Plaster, tile and high ceilings take longer to open and close than drywall.
• Water heater. Replacing, relocating or converting it changes the scope.
• Water service line. Replacing the line from the meter is a separate run, often under hardscape.
• Pressure regulator and expansion tank, where required.
• Permit fees. Our guide to LADBS permit costs explains how Los Angeles fees work.
• Fixture upgrades that older houses may need before the permit is finaled.
• What the walls hide: old leak damage or earlier unpermitted work.

The honest way to get a number is a site visit. Ours take about two hours, and a written proposal follows within 48 hours. Our page on financing options explains how homeowners spread the cost of larger projects.

Permits and inspections in Los Angeles

A repipe needs a permit. LADBS’s plumbing permits page says a plumbing permit is required for any installation or modification of potable water piping. Most single-family repipes skip plan check: the LADBS express permit bulletin (P/GI 2026-003, linked from its express permits page) lists non-engineered domestic water systems with a water service of 1½ inches or less as express plumbing work. Systems needing a 2-inch or larger supply go to plan check. Glendale, Burbank, Pasadena, Santa Monica and unincorporated county areas run their own building departments, so confirm the process locally.

What the inspector checks:

• The pressure test. Water at no less than working pressure, or air at 50 psi minimum; plastic is not air-tested unless the PEX manufacturer allows it; the system must hold for at least 15 minutes without leaking (CPC 609.4).
• Nail protection. Plastic or copper pipe within 1 inch of the face of framing needs a steel nail plate of at least No. 18 gauge, extending 1½ inches beyond the pipe (CPC 312.9).
• Water-conserving fixtures. For alterations to a single-family house built on or before January 1, 1994, Civil Code §1101.4 makes replacing non-compliant fixtures a condition of final permit approval. Non-compliant means toilets over 1.6 gallons per flush, showerheads over 2.5 gallons per minute and interior faucets over 2.2 gallons per minute (§1101.3). This is general information, not legal advice.

Who should do the work

Plumbing contracting in California is the C-36 classification; the CSLB’s C-36 definition covers providing a supply of safe water and disposing of waste. If a general contractor manages your repipe, as we do, ask who will perform the plumbing and check that license too. Our guide on how to verify a contractor’s license in California takes a few minutes.

Planning a repipe with a remodel

The cheapest time to repipe is when the walls are already open. If a kitchen or bathroom remodel is coming in the next few years, doing both together saves cutting into new tile and drywall later, and the patching is already in the remodel budget.

• Kitchens. New sink, dishwasher and refrigerator locations all need supply lines. See our kitchen remodel cost guide.
• Bathrooms. The valve and vanity walls are already open. Our guides to bathroom remodel costs, small bathroom layouts and master bathroom remodels cover the rest, and the order of a bathroom remodel shows where rough plumbing fits.
• Whole-home renovations. When most rooms are open, a repipe adds little disruption. See our whole-home renovation cost guide.
• Rewiring. Houses old enough for galvanized pipe are often old enough for original wiring. If you have knob-and-tube wiring, running both trades through the same openings saves a second round of patching.
• ADUs and garage conversions. A new unit adds fixtures to the property’s water system. See our guides to a garage-to-ADU conversion and legalizing an unpermitted ADU in Los Angeles, where unpermitted plumbing is often part of what has to be opened and inspected.

For fixture and finish inspiration, browse our plumbing design ideas.

Questions to ask before you sign

1. Does the price include the line from the meter, or only pipe inside the house?
2. Which material, which type (PEX-A, PEX-B, copper Type L or M) and which fitting system?
3. Home-run manifold or trunk-and-branch, and where does the manifold go?
4. How many openings, in which rooms, and who patches and paints them?
5. Will water be restored each night, and how long will we be without a kitchen or bathroom?
6. Is the permit included, and who schedules and attends the inspections?
7. Is a pressure reading included, and a regulator or expansion tank if needed?
8. What warranty covers the workmanship, and who do we call if something leaks?

Whole-house repipe FAQs

How long does a whole-house repipe take?

The plumbing typically takes 2 to 5 days, plus drywall patching and the time to schedule the rough and final inspections. More bathrooms, a second story, a slab foundation, plaster walls and tile push it toward the longer end.

Can I stay in my house during a repipe?

Usually, yes. A repipe does not normally require moving out, but the water is off while new lines are connected. Ask whether water will be restored at the end of each day and which rooms will be closed off when.

Is PEX or copper better for repiping a house?

Both are approved under the California Plumbing Code and both last for decades when installed correctly. PEX usually suits concealed runs in an existing house because it needs fewer openings and joints and installs faster; copper suits exposed pipe and owners who want metal. Your house’s layout decides it, not a universal rule.

Do I need a permit to repipe a house in Los Angeles?

Yes. LADBS requires a plumbing permit for any installation or modification of potable water piping. A typical single-family system with a water service of 1½ inches or less is express-permit work with no plan check, and it is inspected before the walls are closed.

Should I replace galvanized pipes if they are not leaking yet?

If you already see low pressure or discolored water, replacing galvanized pipe on your own schedule usually beats waiting for a leak inside a wall. The corrosion cannot be reversed. If a remodel is planned, doing it then avoids a second round of wall openings.

Does a whole-house repipe include the drain lines?

No. A repipe replaces the water supply system. Cast-iron or galvanized drains and the sewer lateral are separate scopes, diagnosed with a camera inspection and quoted on their own.

How much does it cost to repipe a house?

It depends on the number of fixtures and bathrooms, stories, raised foundation versus slab access, PEX versus copper, the wall finishes to patch, whether the water heater or water service line is included, and permit fees. Because those vary so much, we price repipes only after a site visit.

Can I repipe only part of the house?

You can, for example one bathroom during a remodel. The risk is that the remaining old pipe keeps failing and the joints between old and new become weak spots; the California Plumbing Code requires dielectric unions wherever dissimilar metals such as copper and galvanized steel meet. If most of the house is galvanized, a whole-house repipe is usually the better long-term choice.

Get a repipe planned around your house

A good repipe starts with knowing exactly what is in your walls, how the new pipe will travel and what the walls will look like when the crew leaves. We walk the house, map the fixtures, check pressure and access, and give you a written scope covering materials, openings, patching, permit and inspections, so you can compare it line by line with any other quote. Site visits take about two hours and proposals follow within 48 hours. Book one with the buttons below or through our contact page.