plumbing
I am a plumber and need to change the water heater. I always turn off the bypass valve of the water softener before I shut off the water to the house. I just need to know if this step is necessary or could it harm the water softener in any way. Should the bypass valve on the water softener be turn off every time I shut off the water to the house?
Thank you.
With those valve handles in that position, yes, this should shut off the water to your house.
Sounds like you have some misconfigured plumbing somewhere. Trace the plumbing from where it enters your house from the utility and make sure that its first (and only) stop is the water softener.
The power to the softener is only used to run the backwash and recharge cycle. It will continue to operate without power, and will even continue to soften water for a while (though it does eventually need to be recharged, depending on the hardness of your water and how much you use).
Certain types of bypasses can be used as shut-off valves.
A custom-built one with 3 valves is easy: just close all valves.
There's a type with two valves that can also be used: close one (so the valves are in opposite directions).
Other types that only have one valve/control handle don't shut off the water flowing through them.
Separately, you should have a main-shutoff that is reliable. If you have a leak in your house it will likely cost much more than a valve will. Install a ball (quarter turn) valve, rather than a globe or gate valve -- very reliable, and will easily last at least a couple decades.
Best Answer
My only concern would be if you are doing some work UPSTREAM from the softener that might create or dislodge some debris, then switching to bypass will prevent that from messing up the works of the softener.