Running supply lines is a tough, but important job for a homeowner to be familiar with. While it may seem intimidating at first, with the right tools and tips, this is a job that doesn't require professional help. Follow along with our step-by-step instructions to get the job done right, the first time!
Copper is the preferred material for supply lines in most locales, although flexible or rigid plastic is permitted in some areas. Practice cutting copper pipe and sweating joints before you start.
Supply lines are usually routed so they do not cross drainpipes or vents. In most cases, it's easier to make the horizontal runs in the crawlspace or basement. Long runs and bends lower water pressure slightly.
Hammer arresters (Step 3) prevent banging noise when you turn off a faucet. Copper pipe is easily punctured or dented, so position it out of harm's way and install nailing plates to the studs to protect pipes against errant nails. Hot water is always on the left, cold water on the right.
What You Need
- Drill
- Bit and bit extender
- Propane torch
- Fiber shield
- Tubing cutter
- Multiuse wire brush
- Groove-joint pliers
- Carpentry tools for installing braces
- Copper pipe and fittings
- Flux
- Solder
- Damp rag
Step 1: Drill Holes for Pipes
Consult the manufacturer's instructions to position pipes for the shower faucet, sink, and toilet. For example, the shower faucet in this plan calls for vertical pipes 10 inches apart. Use a spade bit attached to a bit extender to drill holes in the center of the wall plate if possible.
Step 2: Install Braces
Install crossbraces so you can anchor the pipes firmly. Cut pieces of 2x4 or 1x4 to fit snugly between studs and attach them by drilling pilot holes and driving screws. If you plan to install a pedestal sink, attach a 2x6 or a 3/4-inch plywood brace (shown) for its bracket.
Step 3: Arrange Pipes
Tie into existing supply lines. Hot and cold stub outs are usually 8 to 10 inches apart and 19 to 23 inches above the floor; consult the manufacturer's instructions to be sure. A toilet stub out is usually 8 inches above the floor.
Dry-fit a complete assembly for the sink and the toilet. For each stub out, use a tee fitting, a 6-inch length of pipe (which you will cut off later), and a cap to protect the pipe. Install a hammer arrester to each.
Step 4: Sweat the Pipes
Sweat all the parts. Anchor the pipes with at least one clamp―preferably two―at each stub out as shown.
How to Secure Supply Lines
A copper supply strap attaches to the face of the studs. Pipes fit into notches or holes, sized and spaced for correct placement. The pipes can be soldered onto the strap using the same techniques as for sweating fittings.
A drop-ear elbow makes the most secure attachment. If you use one, the hammer arrester must be connected to a tee and an elbow just below the drop-ear elbow. Insert a brass threaded nipple into the elbow.
Do supply lines have to run past drain or vent pipes?
To run supplies around an obstruction such as a drain or vent pipe, use four 45-degree elbows. This arrangement makes for smoother water flow and less loss of water pressure than using 90-degree elbows.
Another option is to cut notches rather than holes and run supply pipes in front of the vent pipes. If you do this, be sure to install protective nailing plates, or else the pipes could be punctured by a nail when the drywall is installed.
