When performing home inspections in the Phoenix area, Frequently we find the plumbing at the water softener is not bonded properly. I’m not sure if it’s handy homeowners or negligent contractors who are responsible, but The installation instructions for water softeners are pretty much the same for all the different manufacturers, so the information I’m giving here should apply to just about any water softener.
All of the metallic water distribution pipes in the home are supposed to be bonded; in other words, they’re all supposed to be able to touch each other. If the water pipes in the home weren’t bonded, what would happen if an energized (aka ‘hot’, aka ‘ungrounded’) wire came in contact with one of the pipes? All of the plumbing fixtures and other pipes that were connected would become silently energized. When everything is properly bonded this can’t happen.
I find this bonding compromised by a plastic by-pass valve at nearly half of the water softeners I see. If the water softener manufacturer provides a plastic by-pass valve, they typically will also provide a ground clamp that needs to be installed on the water pipes coming in to and going out of the water softener. (seen in the photo above)
Why water softeners need to be bonded
It is important to understand the reason for grounding/bonding the water pipe system in a house. The electrical service panel is typically grounded via an 8 ft or more ground rod at the meter and/or panel AS WELL AS via a bonding conductor to the metallic water source pipe. (Plastic feeds are not bonded.) The grounding wire is typically #4 copper.
The grounding of the water pipe is not necessary for the proper grounding of the electrical system if there is a separate earth ground supplied (ground rods, etc.), however it is necessary in order to assure an equal ground potential between the electrical system and metallic plumbing system.
The reason for having both the electrical and plumbing bonded at the same potential is to eliminate any possible voltage potential between the two when electrical appliances that contact water are used (electric water heaters, ice makers in fridge, garbage disposals, etc.), and to deal with any accidental contact of voltage to the water system. If this was not done, it may be possible for voltage to appear on the plumbing fixtures.
I hope this can help you understand the issues and how to correct them.
If you have any other questions or wish to book a home inspection in the Phoenix area, please call 480-636-7400