Repiping a lived-in house: what happens room by room

People picture a repipe as a house stripped to the studs. In a finished, furnished house it looks nothing like that. The new lines are flexible PEX, which can be fished through walls and ceilings from a handful of openings, so most of the work is choosing where those openings go and keeping the house livable while they are open. You are still living there, and the kitchen still has to work tonight. Here is how a repipe moves through the rooms of an occupied house, and what you will see along the way.

Planning the route before anything gets cut

Before any drywall comes out, I walk the house and work out where the new lines will run. Out west of Mobile, in places like Semmes and Wilmer, a lot of the houses are newer construction on slabs, and on a slab house the old supply lines often run under the floor. Nobody wants a slab broken up to replace them, so the new lines go overhead through the attic and drop down inside the walls to each fixture. On a house with a crawlspace they can run underneath instead. The route decides where the openings land, and I try to put them where they patch easily: inside a closet, behind the fridge or the washer, on the back side of a wall shared with a bathroom, or down low where baseboard hides the repair. Three small openings in a hall closet beat one long cut across the living room. You see every planned opening before I start.

Bathrooms first, because they hold the most fixtures

A bathroom packs the most connections into the smallest room: a sink, a toilet and a tub or shower valve. The shower valve usually takes the largest opening, because the valve body sits inside the wall behind the handle. Where there is an access panel on the back side, in a closet or the room next door, I work from there and the tile never gets touched. Where there is no panel, I still try to come in from behind rather than through finished tile. New blue and red PEX runs to the valve with crimp rings, and where a short piece of old copper below is staying in service for now, a crimp transition joins the two. Each sink and toilet gets a new shutoff of its own, so any single fixture can be turned off later without shutting down the whole house.

Kitchen, laundry and the heater

The kitchen sink supply usually comes up through the floor of the cabinet or through the wall behind it. Working from inside the sink base means emptying that cabinet for a while, but the wall above the counter normally stays untouched. The dishwasher and any ice maker line get new connections at the same time. In the laundry, the washer box is a ready made opening, and swapping a corroded old box for a new one gives access to the lines behind it without extra cutting. The water heater gets new lines on the house side, and while I am there I check the fittings on top of the tank, which are often the most corroded joints in the building. An outside spigot that has been weeping gets tied into the new lines rather than left hanging on the old pipe.

Testing while the walls are still open

Before any opening gets closed, the new system goes under pressure and every joint I can see gets checked with the water on. Crimp connections are dependable when they are made correctly, and the way to know they were is to test them while the wall is still open, not after it has been patched and painted. I also open every faucet to purge the air and any debris, confirm hot and cold land on the correct sides, and check the pressure at the farthest fixture in the house. A home that had galvanized pipe often feels different afterward, because the old pipe had been closing up from the inside for years and the flow dropped so slowly that nobody noticed. If the water itself carries iron or sediment, new pipe will not change that, and I will tell you so plainly.

Closing up and walking through

Openings get cut square and clean so they patch well, and the cut pieces are kept when they can go back in. I clean the dust and scraps out of each area before moving on, because a repipe in an occupied house gets judged on the mess as much as the pipe. Before the job starts, we settle who handles the final drywall finishing and paint, so nobody is surprised at the end about who is closing what. Some homeowners already have a drywall person they like. Either way, the job ends with a walk through: every opening shown to you, every new shutoff pointed out, and a list of what was replaced. When it is done, you should know your own plumbing better than you did before I showed up.

If you are weighing a repipe, the repiping in Semmes page covers the larger decision, including whole house work versus one bad run. Questions about your own walls can come through the contact page.