Water Softener Installation, Step by Step

Before you start

A do it yourself water softener install is realistic if you've cut and joined pipe before; the job is mostly plumbing, not electronics. Before any water softener DIY job, check local code: many areas require a permit for main-line work, an air gap on the drain and a bypass valve, and some restrict brine discharge to septic systems. Read your softener's manual; flow direction and drain-line diameter rules vary. If you aren't comfortable soldering copper or cutting the main, hire a licensed plumber. Tools: tubing cutter, wrenches, Teflon tape, a bucket and towels.

Water softener system installation steps (HowTo)

1. Pick the spot. Indoors, level, protected from freezing and direct sun, near the main line after the pressure tank (on a well) and before the water heater, with a drain and outlet nearby.
2. Shut off the water and drain the lines. Turn off the main, open a low faucet to drain pressure, and turn off the water heater's power or gas.
3. Fit the bypass valve. Attach the bypass to the control valve. It lets you send water around the softener for service without cutting the supply.
4. Connect inlet and outlet. Cut into the main line and connect it to the softener's inlet and outlet ports, observing the flow arrows. Use the fittings your pipe material requires (PEX, copper or CPVC).
5. Run the drain line with an air gap. Run the valve's drain tubing to a floor drain, standpipe or laundry tub, ending above it with an air gap so wastewater can't siphon back. Most plumbing codes require this.
6. Connect the brine line and overflow. Link the brine tank to the valve and run the brine tank's overflow to a drain by gravity.
7. Fill, program and flush. Add water and salt, set the time and your hardness, put the valve in bypass, slowly open the inlet to purge air, then run a manual regeneration.
8. Test. After the first regeneration, test the softened water. It should read 0–1 gpg. Bring the water heater back on.

Choosing the drain

Regeneration sends tens of gallons of brine to drain in a short time, so the drain has to take that flow: a floor drain, laundry standpipe or utility sink all work. Keep the drain line as short as practical, check the maker's maximum height and length for it, and never connect it to a septic system that local rules say can't take brine.

Common mistakes

• Softening outdoor taps. Branch hose bibs off before the softener; there's no point softening lawn water.
• Drain line taped into the drain. No air gap means a backflow risk and usually a code violation.
• Skipping the pre-filter on a well. Sand scores the valve seals in months. Add a sediment pre-filter.
• Wrong hardness setting. Enter your tested gpg plus about 4 for every ppm of iron, or the softener regenerates too late.
• Installing in a hot garage or freezing shed. Heat warps tanks and freezing cracks valves.

Two-tank vs cabinet installs

Cabinet softeners connect with one valve and one drain hose, so they're the quickest install. Two-tank systems need the resin tank stood upright and level, the brine tank placed within reach of the brine line, and sometimes the resin loaded on site; follow the maker's order for adding gravel, resin and the distributor tube.

Hiring a plumber

Expect a few hundred dollars for a straightforward job, more if the main line has to be rerouted or a drain added. Ask whether the quote includes a bypass, drain line and permit. Costs are covered in our water softener cost guide.

After installation

Check for leaks over the first day, confirm the salt level drops after regenerations, and retest softened water after a week. Ongoing jobs are in water softener maintenance. On a well, also see our water softener for well water picks, which include sediment and iron advice.