Whole-home repiping: replacing the system, not the leak
At some point paying to repair a failing supply system costs more than replacing it. Galvanized that has been narrowing for sixty years, polybutylene at its fittings, or copper on its third slab leak, here is how that decision is actually made.
Ask for the partial-scope number too. The comparison is the useful part.
When repairs stop making sense
Nobody repipes a house because a brochure suggested it. It happens when the arithmetic on repairs stops working, and there are three fairly clear signals that it has.
Repetition. The most reliable indicator there is. One leak is an event, and a spot repair is the right answer. Two leaks on the same system is a pattern. By the third you are paying repeatedly to address the symptom while every remaining foot of pipe is exactly as old and as thin as it was before. Each repair also costs you a hole in a wall or a floor, and in Arizona often a floor you cannot match.
Material with known end-of-life behavior. Galvanized steel and polybutylene do not fail gracefully at one point. They reach a stage and then produce failures in a cluster. A first leak in either is better read as a schedule than as an accident.
Evidence from an open repair. If a plumber has had a section out and the pipe is visibly pitted, thinned or scaled along its length rather than damaged at a point, that is direct evidence about the rest of the system. Ask to see the removed section, it is the most honest diagnostic available and it costs nothing.
There is a fourth, softer signal: declining pressure and volume with no leak at all. That is galvanized narrowing internally, and it does not improve.
The three materials that drive most Arizona repipes
Galvanized steel
Older housing in central Phoenix, the historic Tucson neighborhoods, and the earlier parts of Mesa, Glendale and Tempe. Zinc-coated steel that corrodes internally over decades, building up rust and scale that narrows the bore and eventually thins the wall until it fails at threads and weak points.
Two distinct symptoms, which is unusual. Leaks, and separately a loss of flow, pressure that seems fine until a second fixture opens. Rust-colored water on the first draw after the house has been quiet is the classic tell. Repairing galvanized relocates the problem to the next thinnest spot.
Polybutylene
Grey plastic supply pipe, roughly 1978 to 1995, and present in a great many Arizona homes from that era. It has its own page, polybutylene repipe, because the failure pattern is distinctive: sudden, usually at fittings, and with essentially no warning symptom beforehand.
Copper with a slab leak history
Copper is a good material that has had a hard time in Arizona. Hot, mineral-heavy water works on it from the inside; under a slab, thermal cycling grinds it against concrete and caliche from the outside. Houses from the 1970s and 1980s frequently reach a point where the under-slab hot runs start producing pinholes.
The first one is a repair or a reroute decision. By the second or third, the useful question is not how to fix this leak but what it costs to stop having them, and the answer is usually to abandon the under-slab runs entirely.
On this page
Ask for the removed section
If a previous repair produced a length of old pipe, look at it. Pitting and scale along the whole piece tells you about the whole system. A clean pipe with one defect tells you the opposite.
Why PEX, and why the new pipe goes overhead
Two decisions define a modern Arizona repipe, and both are worth understanding rather than accepting.
The material. PEX dominates residential repiping here for practical reasons. It comes in long flexible coils, so a run can go from the manifold to a fixture with no joints along the way, and joints are overwhelmingly what fails. It absorbs thermal movement without stressing connections, which matters when the pipe lives in an attic that swings through a wide annual temperature range. It is less reactive to aggressive water chemistry than copper. And it can be pulled through existing framing with far less demolition, which shows up directly in your drywall bill.
Copper remains a legitimate choice and some homeowners prefer it. Be clear-eyed about the trade: a fitting at every direction change, each one a soldered joint, and continued exposure to the same water chemistry that shortened the life of the pipe being replaced.
The route. New supply lines go up into the attic and drop down inside walls to each fixture group. Nothing goes back under the slab, and that is deliberate. Every foot of the new system is then reachable with a ladder and a drywall saw rather than a concrete saw, for the rest of the building's life.
The old pipe stays where it is, capped, depressurised, dry and inert. Removing under-slab pipe would mean opening the floor, which is precisely what you are paying to avoid.
The attic insulation question, which separates good work from cheap work
If you read one section of this page carefully, make it this one. It is the most common corner cut on Arizona repipes and it is the one you will notice every day afterwards.
An Arizona attic in July is far hotter than the air outside. Run water lines through that space uninsulated and two things happen. The hot line, having sat all afternoon, delivers water hotter than the thermostat setting on the first draw. And the cold line runs genuinely warm for a long time before anything cool arrives, which people notice immediately at a bathroom tap and find infuriating for years.
Done properly, both lines are insulated along the entire attic run, with the insulation continuous through supports rather than interrupted at every hanger. The pipe is supported at correct intervals so it cannot sag between points or rub against framing, truss plates or ductwork as it moves.
Two questions to ask before signing: what insulation goes on the attic runs, and how is the pipe supported. Both have simple correct answers.
What the work looks like, day by day
A typical single-story Arizona house is a two to four day job for the plumbing, with drywall and paint following afterwards.
Before day one. The route is planned and the access openings are walked with you and marked. Furniture is moved away from work areas and floors are protected. Attic access is established.
Running the new system. The crew works in the attic pulling the new lines and dropping them down inside walls to each fixture group. This is the bulk of the labor and most of it happens above your ceiling.
Connecting fixture by fixture. Each bathroom, the kitchen, the laundry, the water heater and the hose bibs are tied over to the new system. Water is generally off during working hours and restored at the end of each day.
Pressure test and inspection. The new system is pressurized and held before anything closes. Where the municipality requires inspection, that happens with the walls still open.
Isolating the old system. Old runs are capped and left in place.
Then drywall. Patch, texture, paint, usually a separate phase and often a separate trade.
The line is answered by people who do this work.
Access, patching and the texture problem
A repipe needs openings at each fixture group and at top plates where drops come down. That is a real number of holes, and how they are handled makes the difference between a job that disappears and one you look at every day.
Insist on walking the access points before anything is cut. A good crew will already have planned them into closets, cabinet backs, garages, laundry walls and low-visibility surfaces. If framing forces one somewhere prominent, you want to know in advance and have the chance to suggest an alternative.
Then settle the finishing in writing. Arizona walls are textured almost without exception, knockdown or orange peel, and a flat patch stands out badly. Get patch, texture and paint each assigned to a named party before the first hole. This is where otherwise good repipes end in arguments.
What improves, and what a repipe does not fix
Likely to improve: pressure and volume, sometimes dramatically, if you are replacing galvanized. Rust-colored first-draw water, gone. The recurring cost and disruption of repairs, gone. And the accessibility of the whole system for anything that happens in future.
Will not change: hard water. This matters and gets misunderstood. Repiping replaces the pipe, not what flows through it. Arizona water will begin depositing scale in the new system exactly as it did in the old one, fixtures will still spot, cartridges will still seize eventually, and water heaters will still accumulate sediment. If that is your concern, it is a treatment question: water softener installation.
Also will not change: drains. A repipe is the supply side only. If the house also has corroded cast-iron drains, common in the same older housing that has galvanized supply, that is a separate system with its own condition. Worth having a camera run while you are already making decisions.
And not the pressure regulator. If the house runs above design pressure because the PRV has failed, new pipe will live a harder life than it should. Have it checked as part of the work.
Partial repipes are a real option
Repiping is not necessarily all or nothing, and it is worth asking. Replacing the hot side only, or the runs serving the two bathrooms where every failure has occurred, can be entirely proportionate.
The caveat is how the cost breaks down. Most of it is setup, attic access, containment, wall openings, crew mobilisation, and that setup is shared across however much pipe gets replaced. So a partial repipe is rarely half the price of a full one.
Ask for both numbers and look at the marginal cost of doing the rest. Sometimes the additional amount to finish the whole house is small enough that stopping halfway makes little sense. Sometimes it is not. Either way you should see the two figures rather than one.
Better decided calmly than during a failure.
Permits, inspection and documentation
A repipe generally requires a permit and usually involves inspection, and the requirements differ meaningfully across Phoenix, Tucson, the Valley cities, the Pinal municipalities and the smaller districts in Yavapai, Mohave and La Paz counties. The plumbing professional who takes the job handles that process and the inspection scheduling. We are a referral service and do not carry out permitting.
Separately, ask for documentation of the finished system, a simple sketch showing where the new runs go and where the manifold sits. It costs the crew almost nothing at the end of a job, it saves a future plumber from diagnosing pipe that is no longer in service, and it is genuinely useful evidence when you come to sell.
Including the partial-scope option, so you can see the marginal cost.
Questions about repiping
How do I know it is time to repipe rather than keep repairing?
The clearest signal is repetition. One leak is an event. Two on the same system is a pattern. Three and you are on a payment plan for a problem you have not solved, each repair costs money, disrupts the house, and leaves every other foot of pipe exactly as old as it was.
The second signal is material. Galvanized steel and polybutylene both have known end-of-life behavior, and once a house with either starts leaking, the leaks tend to arrive in a cluster rather than singly.
What material will the new pipe be?
In Arizona, PEX for most residential repipes, and there are specific reasons rather than fashion. It comes in long flexible lengths, so a run can go from manifold to fixture with no joints in between, and joints are what fail. It tolerates thermal movement, which matters in attics that get extremely hot. It is less reactive to aggressive water chemistry than copper. And it can be pulled through existing framing with far less demolition.
Copper is still used and is a legitimate choice, particularly where a homeowner prefers it. It needs a fitting at every direction change, each one a soldered joint, and it remains vulnerable to the same water chemistry that shortened the life of what you are replacing.
Where does the new pipe run? Not back under the slab?
Correct, not under the slab. That is one of the main points of doing this properly. New supply lines are routed overhead through the attic and dropped down inside walls to each fixture group, which means every foot of the system is accessible for the rest of the building life.
It also means the abandoned under-slab pipe stays where it is, capped and dry. There is no benefit to removing it and considerable cost in trying.
If the pipe is in the attic, does it survive an Arizona summer?
Yes, with one non-negotiable condition: it must be insulated along its whole attic run, and supported so it cannot sag or rub. This is the single most important quality difference between a good repipe and a cheap one in this state.
An uninsulated attic run gives you hot water that is scaldingly hot on first draw and cold water that runs warm for a long time before anything cool arrives. Ask specifically what insulation is being used and how the pipe is supported.
How many holes get cut in my walls?
More than a reroute and fewer than people fear. A repipe needs access at each fixture group, behind or beside sinks, at shower valves, at the water heater, at the laundry, at hose bibs, plus openings at top plates where the drops come down from the attic.
A competent crew plans them into closets, cabinets, garages and low-visibility walls wherever framing allows, and walks the locations with you before cutting. That walk-through is worth insisting on.
Who patches, textures and paints?
This needs settling in writing before work starts, because it is where repipe jobs go wrong administratively rather than technically. Some plumbers include drywall patching and texture; many hand it to you or a drywall contractor; painting is very often separate.
Arizona walls are almost universally textured, knockdown or orange peel, and a flat patch on a textured wall is glaringly obvious. Make sure patch, texture and paint are each assigned to somebody by name.
How long does it take and can we live in the house?
Most single-story Arizona homes are a two to four day job for the plumbing itself, depending on size, number of bathrooms and attic access. Larger or two-story houses take longer.
Most households stay in place. Water is typically off during working hours and restored at the end of each day, and a good crew will tell you which day each bathroom goes offline. Drywall and paint follow afterwards.
Will water pressure and hot water wait times change?
Pressure usually improves, sometimes dramatically, if you are replacing galvanized, decades of internal corrosion narrow the bore and restrict flow, and new pipe at proper diameter restores it. The classic tell that this was your problem: pressure that collapsed whenever a second fixture opened.
Hot water wait times can go either way depending on how the runs are laid out. If a long wait at a particular fixture bothers you, say so before the layout is planned rather than after, it can influence the design, and it is the right moment to discuss recirculation.
Does a repipe fix hard water?
No, and it is important to be clear about that. Repiping replaces the pipe; it does not change what flows through it. Arizona water will begin depositing scale in the new system the same way it did in the old one.
What it does do is start the clock again with a material less vulnerable to that chemistry. If hard water is a concern in its own right, scale on fixtures, appliances failing early, spotting, that is a treatment question. See water softener installation.
Is a partial repipe a reasonable option?
Sometimes, and it is worth asking about rather than treating repiping as all or nothing. Replacing the hot side only, or the runs serving two bathrooms, can be proportionate where the failures have all been in one part of the system.
The caution is that most of the cost is setup, attic access, wall openings, containment, crew time, and that setup is shared. A partial repipe is rarely half the price of a full one, so ask for both numbers and look at the marginal cost before deciding.
What happens to the old pipe?
It is isolated, capped and left in place. Under-slab runs stay in the concrete; in-wall runs stay in the wall. All of it depressurised and dry, which makes it inert.
Ask for the new layout to be documented, ideally a simple sketch of where the runs go. It saves a future plumber from diagnosing a system that is no longer in service, and it is genuinely useful when you sell.
Should I do this before selling, or leave it for the buyer?
That is your call rather than ours, but two facts are worth having. A documented repipe with new supply lines is a real and verifiable improvement that removes a known concern from a buyer inspection. And a house with a leak history and original galvanized or polybutylene will attract questions either way.
What we would say is that discovering the problem during someone else purchase inspection puts you in a weaker position than dealing with it on your own timetable.
Does a repipe need permits?
Generally yes, and it will usually involve inspection. Requirements differ across Phoenix, Tucson, the Valley cities, the Pinal municipalities and the smaller districts in Yavapai, Mohave and La Paz counties.
The plumbing professional who takes the job handles permitting and inspection scheduling. We are a referral service and do not carry out permitting ourselves.
Third leak in the same house?
That is not bad luck, it is a system at the end of its life. Call and we will connect you with someone who will price the full and partial scope honestly.
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