How to Install a Water Softener Yourself (Parts List + Step-by-Step)
Quick answer: a water softener goes on the main water line where it enters the house, after the branch to your outside taps and before the water heater. You connect the main line to the softener’s bypass valve, run a drain line to a floor drain or standpipe with an air gap, run a separate overflow line from the salt tank, then purge the air slowly, add salt, program it and sanitize it. If you can cut and join pipe, it’s a manageable job; Mid Atlantic Water, which sells do-it-yourself softeners, says a licensed plumber typically finishes in 2 to 3 hours. Check your local code first: some areas need a permit, and Massachusetts requires a licensed plumber.
Where to install a water softener
- On the main line, close to where water enters. Install it near the water meter (city water) or the pressure tank (well water), before the rest of the plumbing, Whirlpool and US Water Systems say.
- After the branch to outside taps. Outside faucets should stay on hard water to avoid wasting softened water and salt, Whirlpool says.
- Before the water heater. Never run hot water through it; Whirlpool limits incoming water to 120°F. US Water Systems suggests connecting at least 10 feet before the water heater.
- Near a drain and an outlet. A floor drain is preferred, Whirlpool says; a laundry tub or standpipe also works. You also need a 120-volt outlet that isn’t controlled by a switch.
- On a solid, level floor, out of the sun and frost. Freezing damage voids Whirlpool’s warranty, and direct sun can distort plastic parts.
- After other treatment equipment. Whirlpool says any other water treatment equipment, such as a sediment filter, goes before the softener. On well water, that means pump, pressure tank, filters, then softener; see our well water guide.
Pre-plumbed homes: the softener loop
Some homes, especially newer ones, have a softener loop: pipes already routed from the main line to a spot for the softener, often in the garage. With a loop, you connect the softener’s inlet and outlet to the two loop pipes, so there’s no main-line cutting. Some states build it into their code; Idaho’s plumbing code, for example, requires a pre-plumbed softener loop in new one- and two-family homes built on a slab or with a finished basement. No loop? This Old House says adding the plumbing can raise a professional install by $200–$800; see our cost guide.
Can a water softener be installed outside?
Sometimes, in climates that don’t freeze. Whirlpool says not to install where freezing temperatures occur and to avoid direct sunlight. US Water Systems allows outdoor installs if you protect the softener from the elements, and says the outlet and power transformer should be inside, out of wet weather. If yours goes outside, a fitted cover helps with sun and rain, but check that your softener’s manual allows it.
Water softener installation parts list
| Part | What it’s for | Notes |
|---|---|---|
| Bypass valve | Lets water skip the softener for service | Included with Whirlpool and Rheem softeners and many Fleck systems; a 3-valve bypass is the alternative |
| Inlet and outlet adapters or connectors | Join your pipes to the bypass valve | Whirlpool and Rheem say sweat adapters aren’t included, so check your box; support the pipes so they don’t strain the valve |
| Pipe and fittings | Route the main line to and from the softener | Copper, PEX, CPVC or other pipe approved for drinking water |
| Drain line | Carries regeneration water to the drain | Whirlpool supplies 3/8-inch hose; the Fleck guide calls for ½-inch ID rigid-wall tubing; A. O. Smith says ¾-inch ID for runs of 25 feet or more |
| Air gap or air gap fitting | Prevents sewer water backing into the softener | 1½ inches (Whirlpool, Rheem) or 2 inches (A. O. Smith) above the drain |
| Overflow hose | Gravity drain from the salt tank if it overfills | Separate from the drain line |
| Ground clamps and #4 copper wire | Keep the electrical ground across a plastic valve | Needed on metal pipe, Whirlpool says |
| Silicone grease, Teflon tape, hose clamps | O-rings, threaded joints, hose ends | No Teflon tape on the Fleck valve-to-tank threads |
| Salt, bleach and test strips | Start-up, sanitizing and checking | Nugget, pellet or solar salt with under 1% impurities |
From Whirlpool’s, Rheem’s and A. O. Smith’s manuals and Quality Water For Less’s Fleck guide.
Your water softener installation checklist
Answer four questions to get a parts and steps checklist for your home.
Choose your options to see your checklist.
How it works: the checklist combines requirements from Whirlpool’s, Rheem’s and A. O. Smith’s manuals, Quality Water For Less’s Fleck guide and US Water Systems’ location advice. Your softener’s manual comes first.
How to install a water softener, step by step
- Prepare. Shut off the electric or fuel supply to the water heater, as Rheem’s manual directs. Set the softener in place on a solid, level floor; Whirlpool warns not to put shims under the salt tank. Fill the resin tank first if your Fleck system shipped empty; Mid Atlantic Water ships its tanks empty with the resin bagged separately.
- Turn off the water. Close the main valve near the meter or pressure tank, then open faucets around the house to drain the pipes. Whirlpool says not to drain the water heater.
- Fit a ground wire on metal pipe. The main pipe often grounds your home’s electrical system, and a plastic bypass valve breaks that path. Whirlpool says to clamp a #4 copper wire across the gap before you cut, and to check your local electrical code.
- Install the bypass valve. Grease its O-rings with silicone grease, push it into the softener’s valve and snap the clips in place (Whirlpool and Rheem), or attach the plumbing adapter to the Fleck valve.
- Cut in and plumb the inlet and outlet. Cut the main line, then measure, cut and dry-fit the pipe from the main to the inlet and outlet. Make sure hard water goes to the port marked IN. Support the pipes so they don’t strain the valve. Don’t solder with the plastic bypass valve attached; the Fleck guide suggests soldering 12-inch sections away from the valve and using a wet rag near joints.
- Run the drain line. Connect the drain hose to the valve’s drain fitting with a clamp, keep the run short and direct, and secure the end over the drain with an air gap so it doesn’t whip during regeneration. Never push the hose into the drain.
- Run the overflow line. Connect a separate hose from the salt tank’s overflow fitting to a drain point no higher than the fitting; it works by gravity. Whirlpool and Rheem say never to join the drain line and overflow line, and Rheem’s troubleshooting lists a tee between them as a cause of problems.
- Purge the air and check for leaks. With the bypass valve in bypass, slowly open the main valve and run water from a couple of cold taps until it flows without air. Then move the bypass to service slowly, pausing to let the softener fill. After about three minutes, run a hot tap until it flows steadily, then close the taps and check every joint.
- Add water and salt. Whirlpool says to pour about 3 gallons of water into the salt tank, then add nugget, pellet or coarse solar salt with under 1% impurities.
- Plug in and program. Use an outlet that isn’t controlled by a switch. Set the time, your water’s hardness and the regeneration time; see how to set the hardness.
- Sanitize. Pour about 3 oz (6 tablespoons) of household bleach into the brinewell and start a manual regeneration. When it finishes, run a cold tap until about 50 gallons have passed, which takes at least 20 minutes.
- Restart the water heater. Turn its power or gas back on. Whirlpool notes the heater is full of hard water and will fill with softened water over a few days as you use hot water; to speed it up, drain it after the first regeneration.
Then test the softened water; under 1 gpg counts as soft. See how to tell if your softener is working.
Water softener drain line: the rules
- Air gap: leave 1½ inches between the end of the hose and the drain (Whirlpool, Rheem), or 2 inches above the flood rim (A. O. Smith), so sewer water can’t back up into the softener. Air gap fittings that sit on a standpipe make this easier.
- Size: A. O. Smith calls for at least ½-inch ID tubing, increased to ¾-inch ID for runs of 25 feet or more. Local code can ask for more: Idaho requires a ¾-inch minimum drain line.
- Height and length: Whirlpool says to avoid runs longer than 30 feet or raising the hose more than 8 feet above the floor; A. O. Smith allows up to 8 feet of rise if your water pressure is at least 40 psi.
- Rigid vs flexible: flexible drain hose isn’t allowed everywhere; where it isn’t, Whirlpool says to run ½-inch copper tubing with a compression fitting.
- Where it can go: a floor drain, laundry tub, sump or standpipe, per your local code. Idaho’s code accepts a washer box with a dual outlet on the same floor or one floor below.
Clogged or slow drain line? A kinked, sharply bent, too-long or too-high drain line can stop the softener drawing brine, Whirlpool’s troubleshooting says. Straighten it, shorten it or lower it.
Parts we’d buy for a DIY install
SharkBite Max flexible water softener connector
A 24-inch stainless braided connector with a 1-inch female thread on one end, for the softener’s 1-inch male connection, and a ¾-inch push-to-connect end for copper, PEX or CPVC pipe. No soldering, so it suits a plastic bypass valve.
- Fits: PEX, copper, CPVC, PE-RT and HDPE pipe (listing)
- You need: two, one for the inlet and one for the outlet
Good to know: check the thread on your softener’s connection first. Whirlpool’s bypass takes adapters rather than direct threads; see the kit below.
Check price on Amazon1-inch install adapter kit (7342704)
Adapters, clips, O-rings and silicone grease for the 1-inch high-flow bypass valves used on many cabinet softeners. The listing says it fits Whirlpool, Kenmore, GE, EcoPure, Morton and NorthStar.
- Contains: 2 adapters, 2 clips, 2 O-rings and silicone lubricant (listing)
Good to know: compatibility comes from the seller; match the part number to your softener’s manual before buying.
Check price on AmazonAir Gap International ET117-008
Sits on a 1½-inch standpipe and takes a ½-inch ID drain tube, holding the hose in place with a built-in air gap and splash guard.
- Flow: up to 15 gallons per minute (listing)
- Also from the same maker: a dual air gap (AG130-001) with a second inlet for a reverse osmosis system
Good to know: check that an air gap fitting meets your local code.
Check price on AmazonSUNICO insulated outdoor water softener cover
A fitted cover with a waterproof outer layer, foam insulation and a foil lining, sized for 48-inch cabinet softeners.
- Size: 16 × 21 × 48 inches, made for Whirlpool WHES30E/WHES40E-size cabinets (listing)
Good to know: a cover doesn’t make a softener freeze-proof. Only install outdoors where your manual allows it and it won’t freeze.
Check price on AmazonStill choosing a softener? The AFWFilters Fleck 5600SXT 48,000-grain is a popular do-it-yourself system with a bypass valve and 1-inch adapter included, per its listing. For more options, see the best water softeners, and size yours first with our size calculator.
How to disconnect or uninstall a water softener
- Put the bypass valve in bypass, so the house still has water, or shut off the main valve.
- Unplug the softener.
- Depressurize the softener side of the plumbing before removing any clips; Whirlpool says to push the bypass valve body toward the softener when you remove them, or the clips can break.
- Disconnect the drain and overflow hoses and the inlet and outlet connections.
- If you’re removing the softener for good, join the inlet and outlet pipes, or leave the bypass valve in place in bypass if it can stay. Use two people to move it; it’s heavy when full of water and salt.
Frequently asked questions
Can I install a water softener myself?
Yes, if you’re comfortable cutting into the main water line and your local code allows it. Massachusetts requires a licensed plumber, and some areas require a permit or inspection.
How long does it take to install a water softener?
Mid Atlantic Water says a licensed plumber typically finishes in 2 to 3 hours. Allow longer for a first DIY install, and less if your home has a softener loop.
How much does professional installation cost?
This Old House puts labor at $150–$1,000, with most standard installations at $500–$700, plus $200–$800 if your home needs new plumbing for a softener loop. See our cost guide.
Does a water softener need a drain?
A salt-based softener does, for regeneration water. If there’s no drain nearby, see our small softeners guide for no-drain options.
Should the water heater get softened water?
Yes: the softener always goes before the water heater, so both hot and cold water are soft. For tankless heaters, see softeners for tankless water heaters.
Related guides
- How much does a water softener cost?
- Best water softeners (all types)
- How to set your water softener’s hardness
- Water softener regeneration explained
Sources
- Whirlpool, WHES48 installation and operation manual (2023): location, air gap, drain and overflow, grounding, bypass, start-up, sanitizing and troubleshooting.
- Rheem, RHS18 installation and operation manual (rev. G, 2025).
- A. O. Smith, AO-WH-SOFT-350C owner’s manual: drain line size, rise and air gap.
- Quality Water For Less, Fleck 5600SXT installation and programming guide.
- US Water Systems, Where to Install the Softener.
- Mid Atlantic Water, How to Install a Water Softener: installation time and shipping.
- Idaho plumbing code amendments via Cornell Law School’s Legal Information Institute: softener loops and drain lines.
- This Old House, How Much Does a Water Softener Cost? (updated June 2026): installation cost, permits and DIY risks.
- Amazon listings for the SharkBite, Air Gap International, 7342704 adapter, SUNICO and AFWFilters products, checked October 2026.