Replacing Galvanized Pipes with PEX Tubing

If your home was built decades ago, chances are that your plumbing system includes galvanized pipes. A common problem with galvanized pipes is that they rust over time and may start leaking sooner or later. Galvanization is a process of coating the steel piping with a thin layer of zinc to create a barrier between the water and steel. Over time, this barrier tends to wear out and exposes steel surface to water, thus causing corrosion.

One of the major disadvantages of galvanized pipes is that calcium in water tends to build up on the inner surface on the pipes, slowly clogging it until the point where water can no longer flow though it. PEX pipe, on the other hand, is not subject to calcium buildup problem. Galvanized steel pipes also face a problem of galvanic or electrolytic corrosion, caused by dissimilarities in conjoined metals. Wherever steel pipe meets copper, the steel will rapidly corrode if a dielectric union isn’t used.

1. It is first necessary to shut off all the water mains.
2. Drain the entire plumbing system, or at least the section where the pipe needs to be replaced.
3. Remove all the galvanized pipes that have to be replaced. Galvanized pipes can be cut using a hacksaw, band saw or a proper metal tubing cutter. Keep in mind that water might still be in the pipes so have a bucket or canister ready to avoid spills.
4. Install a threaded transition fitting to go from galvanized pipe/fitting to PEX tubing. Depending on the type of PEX fittings used, a dielectric union might be needed.
5. Connect the PEX tubing to the fitting using a compatible method.
6. Check connection for accuracy. Pressure test the system to assure leak-free installation.