How to Install a Water Softener
To install a water softener, you cut it into the main cold water line where the supply enters the house, with a bypass valve, a drain line with an air gap, and an outlet for the control. It goes ahead of the water heater so the heater gets softened water. If your house already has a softener loop, it's a half-day job for a handy homeowner; if it doesn't, the plumbing is the hard part and most people hire a plumber.
The steps below follow Pentair's installation instructions for the Fleck 5600SXT, a valve you will find on a lot of homeowner softeners. Your softener's manual wins if it differs.
Where a water softener goes
- On the main line, after the pressure tank on a well or after the meter on city water. Everything after the softener gets soft water.
- Before the water heater. Hard water scales up water heaters, and softening protects it.
- Indoors, in a dry spot that doesn't freeze. Pentair limits its valve to dry locations and says not to let it freeze.
- Near a drain. Regeneration sends water to a floor drain, laundry standpipe or sump.
Penn State says toilets, outside spigots and basement sinks can stay on hard water. Branch those off before the softener if you can. It saves salt, and your lawn doesn't need sodium. Some people also keep one cold kitchen tap unsoftened for drinking.
Tools and parts
- The softener: resin tank with control valve, brine tank, brine line.
- A bypass valve, if the softener doesn't come with one.
- Pipe and fittings to match your house: copper, PEX or CPVC, plus adapters for the valve yokes.
- Pipe cutter, and either a torch kit, PEX crimp tool or push-fit fittings.
- Drain tubing, at least 1/2 inch for a typical house.
- PTFE (Teflon) tape and silicone lubricant.
- A bucket, towels and a level.
Steps
Check your water pressure and temperature
The Fleck valve needs at least 20 psi to regenerate properly and can't take more than 125 psi. Water going in can't exceed 110°F. If your pressure runs high, add a pressure-reducing valve first.
Set the tanks
Put the resin tank and brine tank on a firm, level base where they'll live. Leave room to lift the brine tank lid and pour salt.
Shut off the water and drain the line
Close the main, open a low faucet and let the pressure bleed off.
Cut in the plumbing
Run the supply to the softener's inlet and bring the outlet back to the house line. Watch the flow arrows on the valve; reversed inlet and outlet is the classic first-timer mistake. If you're soldering near the valve, finish all solder joints before you attach the drain line flow control, and keep it at least 6 inches from any solder joint. Heat ruins the part.
Install the bypass
Put the bypass in the bypass position for now. See how to use the bypass valve for what each position does.
Run the drain line
Use 1/2-inch tubing for a typical house, or 3/4-inch if backwash flow is over 7 gpm or the run is longer than 20 feet. Use only PTFE tape on the drain fitting. End it with an air gap above the drain, at least twice the drain pipe's diameter and never less than 1 inch. The air gap keeps sewer water from being siphoned back into your supply.
Hook up the brine tank
Connect the brine line between the valve and the brine tank, and run the brine tank's overflow fitting to the drain separately. Add about 1 inch of water above the grid plate in the brine tank, but no salt yet.
Flush the lines
With the softener still in bypass, turn the water back on and run a nearby cold tap for a few minutes to wash out solder and debris.
Fill the resin tank
Slowly move the bypass to the service position so the tank fills. Go slowly; slamming it full can disturb the resin. When the flow stops, open a cold tap nearby to purge the air.
Plug in and program
Plug the transformer in and set the clock, hardness and regeneration time. Use your hardness test result, not a guess. Our Fleck SXT settings guide covers the buttons.
Run the startup regeneration
Start a manual regeneration and let backwash run until the drain water runs clear, up to 10 minutes. Then step through brine draw (confirm it pulls water from the brine tank), rapid rinse for about five minutes, and brine fill.
Add salt
Pentair says not to use granulated or rock salt. Pellets or clean crystals are the safe choice. Our salt guide explains the difference.
Check every joint for drips over the next day, and test a kitchen tap for hardness after the first scheduled regeneration.
Mistakes to avoid
- No air gap. Jamming the drain hose into the standpipe skips the air gap Pentair requires. Plumbing inspectors look for it.
- A switched outlet. If someone turns the switch off, the clock stops. Pentair says outages over 8 hours may lose the time setting.
- Salt before startup. Pentair's startup steps say to add water to the brine tank but no salt yet.
- Treating the hose bibs. Softened water on the lawn wastes salt.
- Skipping the bypass. Without one you'll have to shut off the whole house to service the softener.
- Iron going straight in. If your water has iron, Pentair suggests an iron filter ahead of the softener when iron is clogging the plumbing. See softeners for well water.
When to hire a plumber
Call a plumber if there's no softener loop and the main line is hard to reach, if you'd need to move a drain, or if the outlet would need a new circuit. Fixr says plumbers charge $100 to $1,000 per installation, and adding a softener loop costs $600 to $2,000. HomeGuide puts a dedicated electrical circuit at $250 to $900. HomeAdvisor says doing it yourself saves $150 to $1,000 in labor.
Many towns require a plumbing permit to cut into the main line. Check with your local building department before you start. Our installation cost page breaks down what pros charge.
FAQ
Can I install a water softener myself?
Yes, if you're comfortable cutting into the main water line and the house has a drain and an outlet nearby. With an existing loop, it's mostly connecting fittings and programming the valve. Without one, a plumber is usually worth the money.
Where should a water softener be installed?
On the main cold line after the well pressure tank or water meter, and before the water heater. Put it indoors in a dry spot that won't freeze, near a drain.
How do you plumb a water softener?
Supply goes to the valve's inlet, the outlet goes back to the house, and a bypass sits between them so you can isolate the softener. A drain line with an air gap carries regeneration water away.
How do I replace an old water softener?
Put the old unit in bypass, shut off the water, disconnect it and remove the tanks. If the new valve's connections differ, adapt the plumbing, then follow the startup steps above. Fixr puts old-unit disposal at $50 to $100 if a pro hauls it away.
Sources
- PentairFleck 5600SXT Downflow Service Manual (opens in a new tab)
- Penn State ExtensionWater Softening (opens in a new tab)
- HomeAdvisorHow Much Does Water Softener Installation Cost? (opens in a new tab)
- FixrWater Softener Installation Cost (opens in a new tab)
- HomeGuideHow Much Does a Water Softener Cost? (opens in a new tab)