How to Install a Water Softener (Step-by-Step Guide)

A water softener goes on your main water line right after the pressure tank, and after any iron filter or acid neutralizer. It needs three water connections (in, out and a drain), a small brine line to the salt tank, and an outlet that is always on.

Every tank ships empty. The resin comes in separate bags and goes into the tank at install, and drain tubing is not included. We recommend a licensed plumber, who typically finishes in 2 to 3 hours, and I support your plumber by phone at 800-460-5810 while he works.

This page walks through the install on the Fleck 5600SXT we ship, in the order your plumber does it.

Water softener installation diagram

The water comes from the pressure tank into the bypass valve, through the softener, and back out of the bypass to the house. The drain line and the brine line both connect to the control valve on top of the softener, and the valve plugs into an outlet.

Where the softener goes in line

On a well, the softener goes right next to your pressure tank, after any sediment filter, iron filter or acid neutralizer. The order matters:

1. Pressure tank. Nothing goes between the well pump and the pressure tank.
2. Sediment filter, to catch sand and grit.
3. Iron filter and acid neutralizer, if your water test calls for them.
4. Water softener.
5. Carbon filter and UV light, if you have them.

The softener goes after the iron filter because iron shortens the life of the resin. It goes after the acid neutralizer because the neutralizer adds hardness as it raises the pH; one buyer wrote that his hardness went to about 8.7 grains per gallon after his neutralizer went in. The softener has to come after it to take that hardness out. One buyer's plumber put the two in backwards, and the buyer wrote that he switched them himself. The full chain, with the reasons, is in the correct order for well water treatment systems.

Leave at least 10 feet of pipe between the softener and the water heater. The Pentair manual asks for that so hot water cannot back up into the softener. On city water, the softener goes on the main line after the water meter and the main shutoff; my city water softener guide covers that setup.

What ships with the softener

Every softener ships with the mineral tank empty: the resin comes in separate bags and is loaded at install, and drain tubing is not included. The bypass valve comes already installed on the control valve, and a fill funnel comes with it. The mineral tank, the control valve (with the bypass on it), the salt tank and the resin ship as separate pieces so nothing is damaged in freight, and it can arrive in more than one shipment.

Buyers have told us there was no instruction sheet in the box. The Pentair manuals are free, and I link them in my Fleck 5600SXT owner's guide.

What your plumber brings

Every house is plumbed differently, so your plumber supplies the fittings from any hardware store. Have them on hand before install day:

• Two 1 inch threaded adapters to match your pipe. The bypass also works on 3/4 inch pipe with adapters.
• 90-degree elbows and couplings to match your pipe type, and about a couple of feet of pipe.
• 1/2 inch flexible drain tubing long enough to reach the drain, and a clamp.
• Plumber's tape for the threads.
• Plain pellet softener salt for after startup.

Know your pipe before anyone buys fittings. A lot of homes now have CPVC or PEX, and both are easy to work with: CPVC glues and PEX crimps, or takes push-on SharkBite fittings. A lot of older homes have copper, and that is a different story, because the joints are soldered. If you have copper and no experience with a torch, that is the part to leave to a plumber.

What to tell your plumber: "It is a Fleck 5600SXT water softener with a 1 inch bypass valve. It needs a connection in and out on the main line, a 1/2 inch drain line to the nearest drain, the 3/8 inch brine line to the salt tank, and an outlet that is always on."

Not sure which fittings to buy?

Text Aidan a photo of your pipes

Send a photo of the pipe where the softener will go, and I will help you or your plumber with the fittings and the setup.

Text Aidan443-277-2204 Call800-460-5810Aidan

8 AM to 5 PM Eastern, seven days a week. A real person, not a call center.

The nine installation steps

The install is nine steps, and the one that matters most is turning the water back on slowly. Your plumber does them in this order; I walk through the same install in the video.

Since the video was made, every softener ships with the resin in separate bags, so loading the resin is part of every install now.

1. Pick the spot next to the pressure tank

   The softener goes right next to your pressure tank in the basement, on a fairly level spot with room for the resin tank and the salt tank side by side. It needs a drain within 20 feet that sits lower than the valve, an outlet that is always on, and a spot that never freezes. Then lay out the fittings: how many 90-degree elbows, which male and female adapters, and how much pipe.

2. Shut off the water

   Turn off the well pump at its breaker (or close the main shutoff on city water) and open a cold faucet to let the pressure off. Keep a bucket and towels under the pipe that gets cut; there is always some water left in the line.

3. Load the resin into the tank

   Before the valve goes on, tape over the top of the center tube that sticks up inside the tank, set the funnel on the tank opening, and pour or scoop the resin in. Use all the resin that comes with the unit. Take the tape off when you are done. If any resin gets into the center tube, it is a huge problem later, so that tape is the step not to skip.

4. Connect the plumbing to the bypass

   Set the valve on the tank, then cut into the main line after the pressure tank and any other treatment tanks. The water coming in has to go to the inlet port of the valve. Use plumber's tape on the threads, and do not let the pipes hang on the valve or the bypass: "make sure you don't have any tension on the bypass pulling it down or pushing it up." If the joints are soldered, the adapters go on the bypass only after the pipe has cooled. If the house has metal pipe, a grounding strap from the hardware store keeps the plumbing grounded across the softener.

5. Run the drain line

   Push the 1/2 inch tubing over the drain fitting on the back of the valve, clamp it, and run it to the drain. Where it ends matters more than anything else on this line: see the drain line needs an air gap.

6. Connect the brine line

   The salt tank comes with a 6 foot piece of 3/8 inch tubing. Push one end into the quick-connect fitting on the safety float inside the salt tank, run it over to the valve, and connect the other end to the brass fitting on the side of the valve. That is it.

7. Turn the water on slowly

   Open a cold water faucet somewhere in the house first. Then open the main valve slowly, maybe a quarter turn, just to get the water flowing, and let the tank fill up gradually. Do not turn the water on all the way: it will push the resin into your pipes, and that is a plumber and a lot of money to clean out. Once water comes out of the faucet, open the valve gradually to full pressure and let it rinse for 10 minutes. Check every connection for leaks and drips while the pressure comes up.

8. Program the three settings

   Plug the valve in and set three things with the buttons on the screen: the time of day, the capacity (48 for the 48,000 grain, 64 for the 64,000), and your hardness. For the hardness, take your raw water hardness and add 6: if your raw hardness is 5, that is 11, and I would set it to 12 to compensate a little. Do not change any of the other settings; they come preprogrammed. The button presses for each setting are in my Fleck 5600SXT owner's guide.

9. Add salt after the first regeneration

   Hold the Extra Cycle button for 5 seconds to start a regeneration, and watch the drain line while it backwashes: the flow should stay steady, and the tubing should stay put where it ends. That first run is also how you know the drain line is secure. Then fill the salt tank with plain pellet salt, never rock salt. Expect some air bubbles and sputtering at the faucets for the first few days; any time pipes are cut, some air gets into the lines, and it clears on its own.

The drain line needs an air gap

A softener needs a drain because when it regenerates, it rinses the resin with salt water to recharge it, and that rinse goes down the drain line. The drain line is 1/2 inch tubing, not included, that runs from the back of the valve and ends above the drain, never inside it.

The air gap is what keeps drain water from being pulled back into the softener. The Pentair manual says never to push the drain line into a drain, a sewer line or a trap, and plumbing codes say the same thing in their own words: the International Plumbing Code treats softener drain water as indirect waste, which has to drop through an air gap or an air break into a drain that has a trap. Local codes vary, and your plumber knows yours.

If there is no washing machine drain or laundry tub nearby, the drain line goes to a tee cut into a vertical PVC drain line with a P-trap and a standpipe. When plumbers call me about it, I tell them they need a P-trap and a standpipe. That is real plumbing, and it is the one part of this job most worth a plumber. The drain line can run 10, 15 or 20 feet to reach it. One buyer ran his along the basement ceiling to a PVC drain and wrote that the softener "pushes the water up just fine."

The water leaving the valve comes out with some force, so tie the end down wherever it drains. If you have an iron filter beside the softener, the two drain lines can tee into one: "We come off of both and tee it into one and run a single line to the drain." Set the two valves to regenerate at different times so they never backwash together.

The salt tank has its own overflow fitting on the side. The safety float inside it is what keeps the salt tank from overfilling, so the overflow is optional. If your plumber connects it, it gets its own 1/2 inch line to the drain, never tied into the valve's drain line and never higher than the fitting.

What the bypass valve does

The bypass valve takes the softener out of the line so the house keeps water while the softener is worked on. Ours is 1 inch stainless steel, and it ships already installed on the back of the control valve, so the plumber connects to the bypass, not to the valve itself.

The handle has an arrow. Pointing at SERVICE, the water goes through the softener; that is where it stays day to day. Pointing at BYPASS, the house gets unsoftened water straight through, which is what you want while anything on the softener is being worked on.

If it drips at the bypass after the install, check that the clips are tight, the O-rings are seated, and the pipe is not pulling on it. Only 100% silicone grease goes on those O-rings, never petroleum grease.

Common water softener installation mistakes

These are the install mistakes to watch for, with the fix for each.

Something not working after the install? My water softener troubleshooting guide goes symptom by symptom.

What buyers wrote about the install

These are verified purchases from our product pages, newest first.

Frequently asked questions