Use nonmetallic water supply line, you’ll need a jumper wire

Q. I enjoy your newspaper column. However, I question your advice to replace metal piping with 18 inches of PVC piping for the magnetic water softener. In many homes the electrical grounding is connected to the piping close to the electrical panel. It’s not right, I agree, but it is common. The plastic piping will interrupt the path to ground and the home and residents may not be protected.

I also do not believe PVC is approved for indoor plumbing – perhaps you meant CPVC? Finally, if copper is used to replace a section of galvanized piping, please recommend it be connected with insert connections to prevent corrosion and subsequent leakage. A house should be thought of as a series of systems, an alteration to one may have adverse effects on another.

— Respectfully, Tom T. (American Society of Home Inspectors Member #204523), Spokane

A. Tom, thanks so much for your response. Unfortunately, limited space is allotted in the Voice for the column so I am frequently unable to explore all the possible side effects. Consider the following elaboration as “Part 2” of the May 20 article and answers to your questions.

The magnetic device referred to in the article is a magnetic water conditioner and has been manufactured in the United States since 1985.

At least two magnetic water conditioners are needed on the incoming water supply between the water meter and the water heater spaced about 1 inch to 1 1/2 inches apart. Then install two booster units on the water heater: one on the cold water supply entering the tank and one on the hot side as it exits the tank. The magnets won’t work if you have galvanized steel or iron plumbing pipes; however, you can replace the pipe with a minimum of 18 inches of new pipe (CPVC, copper, or approved indoor plumbing material) on either side of the magnetic units. Note that a permit may be required.

If you replace a section of the water line with any nonmetallic water supply line, then the home’s electrical path to ground will be interrupted. This is easily remedied by installing a jumper wire over the replaced areas. For 200-amp service, the jumper should be #4 copper wire. Connect one end of the ground wire with a grounding clamp to one side of the metallic water pipe and carry the other end of the wire over the length of the non-metallic water supply line. Connect it to the other metallic water pipe with a grounding clamp.

While we are on the subject, you’ll need two “dielectric unions” to make the connection if copper is used to replace the section of galvanized piping. If water conditions aren’t right, the mismatch of these two dissimilar metals, i.e. the connection, will fail in a few years through electrolytic corrosion. These unions have one side made of brass and the other of galvanized iron. The nut that draws them together, however, is isolated by a plastic washer that keeps the metals from contacting. Unfortunately, these dielectric unions will break the path to ground, as discussed above. Again, place a jumper ground on the pipes before and after the new section in order to link the pipes.

Those who don’t have a water softener or who are considering one might want to check into the magnetic water conditioner as an alternative. For those readers who clipped and saved the May 20 article, clip this one and file with the first.