A whole-house water filter installed on the main supply pipe will treat all of
the water in your house. To install properly, there should be a shutoff valve
on either side of the filter – the supply side and the house side. If you
don’t have one on the house side, you will need to install one, in addition to
the valve on the supply side. (Note: To get the proper fittings to complete
this project, refer to the documentation accompanying your chosen filter.)
Installation kits are available for most whole-house filters (sometimes sold
It’s important to select a location that is conveniently accessible so that you can access the unit to change out filters. Another consideration: Choose a site that is next to an existing shut off valve.
Cut Pipe and Install New Shutoff Valve
Shut off the water supply to the house.
Cut into the water supply line near a shut off valve – follow the manufacturer’s instructions to ensure you cut away enough pipe to accommodate the filter, the new shutoff valve(s), and any connecting fittings.
Install a shutoff valve on the house side of the supply line – if you are sweating the valve, remove the insides of the valve before applying heat.
Assemble the Parts and Mark for Cutting
Dry-fit as many fittings as possible. You may need an adaptor on either side of the filter in order to join your size and type of pipe.
Mark the final piece for cutting by holding the pipe in place against the end of the shutoff valve.
Install the Filter
For each connection, slide on a nut, then, slide the compression rings in place snuggly and tighten the nuts.
Turn the water back on and check for leaks.
Add a Jumper Cable if Needed
Check to see whether your electrical panel has its ground wire attached to the pipe or to a rod driven into the ground. If the ground wire is attached to the pipe, you will need to add a jumper cable to restore an important safety feature that prevents the filter from interrupting the ground path.
Install grounding clamps on either side of the filter and run a thick wire from clamp to clamp and secure tightly.