Repipe plumbing is one of those projects that hides in the walls, then changes how a house feels every day. When you do it right, showers don’t sputter when someone flushes, water runs clear and hot without a long wait, and leaks stop keeping you awake at night. When you do it wrong, you inherit a lifetime of pinhole repairs or fittings that creep loose in the attic. I’ve overseen full-house repipes in 600-square-foot bungalows and sprawling two-story homes, and I’ve opened enough walls to see every choice play out over time. If you’re trying to decide between copper and PEX, this guide walks you through the real trade-offs, not the marketing one-liners.
Why a full repipe enters the conversation
Most owners don’t decide to repipe because they love the idea of new plumbing. They decide after the fourth leak in twelve months, or when a slab leak turns a bedroom into a marsh. Galvanized steel lines choke on rust and scale until flow drops to a trickle. Some polybutylene systems from the late 80s and early 90s fail abruptly. Copper runs along coastal areas corrode early if the water chemistry is aggressive. At some point, patching stops making sense. When your piping is a failing system, not a single leak, repipe plumbing is the honest fix.
A whole-house repipe replaces your existing domestic water piping with a new distribution system, typically copper or PEX. You’ll be cutting into walls and ceilings, steering new lines to every fixture, and often upgrading the main shutoff, pressure regulator, and water heater connections. Good plumbers can do this with surgical precision, staging drywall patches to blend in and keeping water on for much of the project. But the guts of the decision sit with material: copper versus PEX.
How water actually moves in a home
Before comparing materials, understand the shapes these systems take. A traditional copper repipe often uses a trunk-and-branch layout. Picture a main hot and cold line running the length of the house, then teeing off to feed each faucet, toilet, and shower. That design uses fewer total feet of pipe in many homes but creates some bottlenecks and shared pressure drops when multiple fixtures run.
PEX opens up another approach called a home-run manifold. A central manifold sits near the water heater or mechanical room, and an individual PEX line runs from the manifold to each fixture. Hot and cold each get their own ports. That layout gives you more balanced pressure and the convenience of shutting off a single bathroom without touching the main. It uses more linear footage but often fewer fittings hidden in walls, which matters when you care about leak risk down the road.
Both materials can run either way, yet copper favors trunk-and-branch because soldering a manifold with dozens of ports is pricey and bulky. PEX makes manifolds sensible.
Copper’s arguments: durability with caveats
Copper has history on its side. Walk into houses from the 1960s and 1970s, open a wall, and you’ll still find copper running strong. Done right, it has a service life measured in decades, very often forty to sixty years, and sometimes much longer. It’s rigid, so it holds straight lines and drops. It handles heat well, shrugging off 140-degree water without a second thought. It remains stable in sunlight and is code-approved everywhere. And when you solder it correctly, the joints are predictable and permanent.
Still, copper is not bulletproof. Two quiet enemies cause early failures: water chemistry and erosion Repipe Plumbing Canby corrosion. Aggressive water with low pH can eat copper from the inside, leading to pinholes. If your city water runs around a pH of 6.5 or below and you don’t have neutralization, copper can fail much sooner than you’d hope. Erosion scars show up where high velocity passes through elbows and tees, especially near the water heater. I’ve replaced sections with a constellation of pinholes in homes that ran 80 to 100 psi and used small diameter lines that pushed velocity too high. The fix isn’t just material, it’s also right-sizing and controlling pressure.
You need heat to work copper, and that means open flame in a wood-framed structure. Good plumbers control that risk with heat mats, spray bottles, and saner choices about when to switch to press fittings, but if you’ve seen a charred stud behind a patch, you respect the risk. Copper also carries a price tag that swings with commodity markets. In recent years, material cost for copper has often run two to four times higher than PEX for the same home, and labor is usually higher because of the time it takes to prep, heat, solder, and clean joints.
One last note: copper gets stolen. If you’re doing phased work or leaving materials on site, copper draws more attention than coils of PEX.
PEX’s arguments: speed, flexibility, and quieter lines
PEX, or cross-linked polyethylene, changed the repipe calculus. It bends around corners without elbows, snakes through tight framing, and installs fast with fewer fittings. The flexible runs make for quiet pipes. Many homeowners notice fewer hammering sounds after switching from old rigid lines. Even in attic runs where temperature shifts are intense, PEX tolerates expansion and contraction with far less stress.
PEX types matter. PEX-A is the most flexible with excellent shape memory and uses an expansion method for fittings. PEX-B is stiffer and usually uses crimp or clamp rings. Both work, but expansion PEX-A shines when you’re fishing long runs and trying to minimize fittings in inaccessible spaces. The pipe relaxes and straightens over time, which helps it lay clean.
PEX hates ultraviolet light. Sun exposure breaks it down, so exposed runs outdoors must be protected, and attic skylight leaks can age the surface. Inside walls, it’s fine. In mechanical rooms or garages with some daylight, you use sleeves or paint to block UV. It also doesn’t like high chlorine dioxide levels used by some municipalities for disinfection. If your water treatment includes that, check manufacturer compatibility data and your utility water report. Many PEX failures you see online come from incompatible chemicals, bad crimp technique, or knockoff fittings, not the pipe itself.
Freeze performance tilts toward PEX. While neither material is a freeze pass, PEX can survive a freeze-thaw cycle that would split copper like a ripe melon. In cold-climate attics or crawlspaces, that extra resilience buys peace of mind when power fails and pipes aren’t perfectly insulated.
Cost leans to PEX. With fewer hours of labor and cheaper materials, a typical single-story repipe can drop by thousands compared to copper. Savings get bigger in complicated framing where snaking a rigid material would demand more demolition.
Taste, odor, and water quality considerations
People worry that plastic pipe affects taste. In new PEX systems, a slight plastic scent can carry for a week or two, especially on hot lines. Flushing helps, and the effect fades. Many homeowners never notice any change after the initial period. Copper has no plastic taste, but aggressive water can pick up a metallic tint if corrosion is underway. I’ve had customers in older buildings report blue-green staining at fixtures, a sign of copper leaching. That’s a water chemistry problem more than a material problem, and the proper fix involves conditioning.
As for purity, both materials meet drinking water standards when certified. PEX is tested for leaching under NSF standards, and copper is time-tested but not immune to chemistry. If water quality is a top priority, request U.S.-made, third-party certified PEX with documented chlorine resistance, or specify Type L copper and confirm your local water pH and disinfectant method. Pair either system with a well-maintained whole-house sediment filter when sediment is present, especially on private wells.
Pressure, flow, and pipe sizing
The physics don’t care about branding. Flow depends on diameter, length, fittings, and pressure. Copper’s interior is smooth when new, then roughens slightly with age. PEX’s interior stays smooth. At the same nominal size, PEX has a slightly smaller inside diameter depending on the brand and type, but reduced fittings along the run often cancel the difference. In real repipes, I routinely see better shower performance with a PEX manifold layout than with undersized copper trunk-and-branch systems, even when copper nominal sizes are larger. That’s because each fixture has its own path, so pressure drops from a running dishwasher don’t strangle your shower.
Sizing still matters. Half-inch hot and cold home-run lines to every fixture work for most sinks and toilets. Showers and tubs often warrant three-quarter-inch trunks feeding a manifold or larger home-runs if you have multi-head setups. Keep static pressure in a safe window, ideally 55 to 70 psi. Install or adjust the pressure reducing valve if your supply sits around 80 psi or higher. If you do copper, understand that velocity should stay below roughly 8 feet per second in cold and 5 feet per second in hot to reduce erosion corrosion. That means checking flow and diameter, not just copying what was there.
Fittings: the quiet failure points
Pipes rarely fail. Fittings do. Every tee, elbow, coupling, and transition is a chance for human error or material creep. Copper fittings rely on properly cleaned, fluxed, and soldered joints. Bad flux residue can invite corrosion. Excess heat can anneal the copper or scorch framing. Press fittings reduce open flame risk and speed work, but they cost more, and the quality of the press tool and calibration matters.
PEX fittings come in several flavors. Crimp rings and insert fittings are widely used, reliable when measured with a go/no-go gauge, and fast. Stainless clamps are forgiving in tight spaces. Expansion fittings for PEX-A create a full-bore connection and are hard to mess up if you follow temperature and expansion ring rules. Push-to-connect fittings are excellent for repair work but are not my first choice for hidden permanent joints unless the manufacturer and local code agree and you’re dealing with access panels.
A good repipe plan reduces hidden fittings. Long PEX home-runs do this naturally. With copper, owning the layout helps, but you still need more elbows to navigate framing. Whichever route you take, insist on mechanical protection where pipes pass through studs and plates, so that future drywall screws don’t hit them. Nail plates are cheap insurance, and they’re required by code when clearances are tight.
Fire, attic, and crawlspace realities
Real houses are not plans on paper. In attics with summer temperatures cresting 140 degrees, copper keeps its composure. PEX survives, but it expands and contracts. Secure it with supports that allow some movement, use proper bend supports, and keep it off sharp edges. Insulation matters for both materials. Hot water lines should be insulated to reduce wait times and save energy, and cold lines in humid climates should be insulated to prevent condensation drips.
In crawlspaces, rodents are a factor. I’ve seen them gnaw PEX when it carries warm water in winter. It seems to draw their attention more than cold runs. Copper is unappetizing to rodents. If you choose PEX, add protective sleeving, route lines through bored joists rather than open strapping where feasible, and keep bait and exclusion measures up to date.
For fire safety, copper doesn’t burn. PEX is a plastic and will soften or melt under direct flame, though behind drywall it’s shielded according to standard residential fire ratings. If you’re renovating a garage or furnace room where open flames or UV exposure are likely, run short copper stubs and transition to PEX deeper in the wall, or sleeve and shield the PEX appropriately. Most code books spell this out, and a conscientious plumber will walk you through it.
What projects really cost and how long they take
Budgets vary by region, story count, and access. For a typical single-story, two-bath home with decent attic or crawl access, a copper repipe might land in the 12 to 20 thousand range, while PEX could come in 8 to 14 thousand. Multi-story homes, slab foundations that force you into attic drops, and patch-plaster finishes raise numbers fast. If you’re combining the work with a water heater relocation, add more.
Time on site for a competent two-person crew often ranges from two to four days for PEX, three to six for copper, plus finish work from a drywaller and painter. Water is usually off for several hours each day at tie-ins, then restored overnight. Plan your family’s routine around those windows. A good contractor stages the sequence so your kitchen sink or at least one bathroom stays live as much as possible.
Permits are not optional. Inspections catch missed nail plates, pressure tests, and water heater relief line misroutes. You want that second set of eyes.
Warranty, lifespan, and resale value
Manufacturers offer long warranties on PEX piping, often 25 years or more, with shorter terms on fittings depending on type. Copper does not come with a manufacturer warranty in the same way, but licensed plumbers usually warranty their workmanship. For resale, buyers rarely distinguish if the system is recent and tidy. Realtors like to see “New repipe in 2023” in a listing. In high-end custom homes, copper repipes sometimes carry a perception advantage, especially where exposed mechanical rooms show off polished manifolds and straight runs. In tract homes and rentals, smart buyers are happy with PEX as long as it’s professionally installed and documented.
Actual lifespan depends on water quality, pressure, installation quality, and design. Well-installed copper in neutral water with controlled velocity can outlast PEX. In aggressive water, PEX can outlast copper. This is why blanket claims are misleading. The right choice aligns with your local conditions.
Safety and health: lead, leaching, and peace of mind
Modern copper systems use lead-free solders and brass, but older homes sometimes hide legacy brass valves with higher lead content. A repipe clears most of that out. PEX systems rely on polymer science, and certified pipe types are tested for extraction levels. If you have health concerns, ask your plumber to specify pipe and fitting brands with NSF/ANSI/CAN 61 and 372 certifications and to avoid unknown third-party fittings. After any repipe, flush lines thoroughly and clean aerators. Replace old supply stops and supply lines at fixtures while you’re there. Small details add up to peace of mind.
Where each material wins
If you pressed me for a clean verdict, I’d resist, because houses don’t come in clean categories. Instead, here’s how the edges look in practice.
- Copper wins in homes with high attic temperatures and long exterior exposures where UV protection would be tricky, in markets where craftsmanship and resale optics favor metallic systems, and where water chemistry is friendly and pressure is controlled. PEX wins in repipes that need speed and lower cost, in complex framing where reducing fittings cuts leak risk, in freeze-prone regions, and where a manifold layout can solve chronic pressure drop complaints without upsizing every trunk.
Both can be mixed. I often run copper risers near the water heater, stub-outs at visible fixture connections, and PEX in the walls and ceilings. That hybrid approach keeps UV and heat-sensitive sections in copper, gives you sharp-looking straight stub-outs for tile backsplashes, and leverages PEX’s flexibility where it matters.
How to prepare your home and vet your contractor
Even a flawless repipe makes a mess if you’re not ready. Move furniture away from wet walls, clear under-sink cabinets, and empty linen closets that back to bathrooms. Cover electronics. Expect drywall cuts at shower valves, tub spouts, behind toilets, at the water heater, and near manifolds. Ask for daily cleanup and plastic sheeting for dust control.
When you interview contractors, skip the sales gloss and go straight to process. Ask how they pressure test, whether they use nail plates on every stud crossing, what brand of pipe and fittings they install, and how they protect PEX from UV in garages or mechanical rooms. If copper is on the table, ask whether they use open flame or press fittings near wood, and how they handle fire protection during soldering. Verify that permits are included and that patching and painting are either part of the bid or clearly excluded so you can plan.
A field note on slab leaks and reroutes
If you’re dealing with a slab leak, you face a fork in the road. One path is jackhammer, repair, and re-cover. The other is a whole-house or partial reroute above the slab. Copper buried in concrete is not my first choice anymore. Some builders sleeved copper in plastic through slabs, which helped, but not enough. Rerouting with PEX in the attic or walls avoids future slab excavations and finds sensible pathways for future service. Copper can reroute too, but every turn in an attic increases fittings and the labor bill. In my experience, when a slab leak pushes the conversation, PEX reroutes paired with insulation and careful protection give the best long-term result for cost and serviceability.
Practical differences you’ll notice after the repipe
Homeowners often report three things after a repipe. First, water runs clearer and tastes better, simply because sediment and corrosion are gone. Second, hot water reaches fixtures faster if the layout shortened hot runs, or slower if the manifold sits farther than the old trunk. If delayed hot water bothers you, ask about a dedicated recirculation loop or a demand-controlled recirc pump during planning. Third, noise changes. Copper can ping as it expands with hot water, a manageable quirk with proper clips and sleeves. PEX keeps things quieter. Hammer arrestors at quick-closing valves like washing machines help either way.
What to do if your water is unusual
Private wells, high mineral content, or disinfectants like chloramine or chlorine dioxide change the playbook. Get a recent water test or request your municipality’s water quality report. With copper, you might add a neutralizing system for low pH. With PEX, confirm the pipe’s chlorine resistance rating and stay with recognized brands whose data sheets explicitly cover your disinfectant. If iron or manganese runs high, install prefiltration so that grit doesn’t sandblast your fittings over time.
A simple decision framework
If you’re stuck, use a bias-to-fit approach that accounts for your house, not the internet. Here’s a crisp way to decide without drowning in hypotheticals.
- Your water pH is neutral to slightly alkaline, your attic is accessible, and you value traditional materials and maximum heat tolerance. Go copper, Type L, with careful attention to velocity and pressure. Your water chemistry is aggressive, you want faster installation and lower cost, or your framing makes rigid runs a demolition marathon. Go PEX, preferably PEX-A with expansion fittings, using a central manifold and minimal hidden joints. You want the best of both. Run copper stubs and near-appliance sections, PEX for long distribution runs, insulate everything that carries hot or cold through unconditioned spaces, and protect PEX from UV.
The repipe day, step by step
A well-run repipe feels surprisingly orderly. Here’s the short version of what to expect when the crew arrives.
- Walk-through and layout confirmation, valve locations marked, access points planned. Drop cloths and plastic go up. Water off. Tie-ins at the water heater and main shutoff start. Old lines are isolated, new trunk or manifold goes in. Branch runs to fixtures, pressure test to code, then a longer overnight static test if the schedule allows. Inspection. Drywall patches. Final fixture connections, aerators cleaned, lines flushed hot and cold. Labeling. If you have a manifold, each run gets a clear tag: kitchen hot, hall bath cold, laundry hot. You’ll thank yourself later.
Final guidance born from too many crawlspaces
Don’t chase perfection, chase fit. Copper and PEX both provide safe, clean water when installed properly. The horror stories you hear usually begin with corner-cutting or ignoring context. If your water eats copper, respect the chemistry. If your attic bakes and you have a sun-lit garage, respect PEX’s UV limits. Keep pressure sane. Size lines thoughtfully. Minimize hidden fittings. Document the system with photos before the walls close.
Repipe plumbing is disruptive, but it gives something back every day. Better showers. No mystery drips. The quiet confidence that the heart of your home’s water system is new and built the right way for your conditions. Choose copper, choose PEX, or choose a hybrid, but choose with clear eyes and a plan tailored to your house. That’s how you stop fixing leaks and start living with a system that just works.
Business Name: Principled Plumbing LLC Address: Oregon City, OR 97045 About Business: Principled Plumbing: Honest Plumbing Done Right, Since 2024 Serving Clackamas, Multnomah, Washington, Marion, and Yamhill counties since 2024, Principled Plumbing installs and repairs water heaters (tank & tankless), fixes pipes/leaks/drains (including trenchless sewer), and installs fixtures/appliances. We support remodels, new construction, sump pumps, and filtration systems. Emergency plumbing available—fast, honest, and code-compliant. Trust us for upfront pricing and expert plumbing service every time! Website: https://principledplumbing.com/ Phone: (503) 919-7243