What You Need Before You Start

A Rheem water softener installation requires access to your main water line, a drain, and electrical power. You will need to shut off your water supply, cut into your existing plumbing, and connect the softener between your meter and the rest of your house. Most homeowners can handle this if they have basic plumbing experience and the right tools. If you are not comfortable working with copper or PVC pipe, or if your water line is buried or in a difficult location, hire a licensed plumber instead.

Before you buy, confirm that your Rheem model fits your space. Measure the height, width, and depth of where you plan to install it — usually in a basement, garage, or utility room. Check that you have a floor drain or a way to run a drain line outside. Verify that you have a 120-volt outlet within reach, or plan to have one installed. If your water pressure is above 80 psi, you will also need a pressure-reducing valve on the inlet line.

Key Takeaways

  • Shut off the main water supply and drain the line before you cut into your plumbing.
  • Install a bypass valve on the inlet side so you can service the softener without shutting off water to the whole house.
  • Connect the drain line to a floor drain, laundry sink, or outdoor drain — never to a septic system without checking local codes first.
  • Fill the brine tank with the salt type specified in your manual, usually pellets or crystals, and run the regeneration cycle before normal use.
  • If your water pressure exceeds 80 psi, add a pressure-reducing valve upstream of the softener to prevent damage.

Shutting Off Water and Preparing the Line

Locate your main water shutoff valve, usually near the water meter or where the line enters your house. Turn it clockwise until it stops. Open the lowest faucet in your house — a basement sink or outdoor spigot — to release pressure and drain the line. Leave that faucet open while you work.

Decide where to cut. The softener must go between your meter and the rest of your house, before any branch lines split off. If you have a water heater, the softener goes before it. Mark the spot on the pipe where you will make your cut. Use a pipe cutter (for copper) or a hacksaw (for PVC) to cut straight across. Remove any burrs with a file or deburring tool. If you are working with copper, you will need a torch, solder, and flux to rejoin the pipes later. If you are working with PVC, you will need PVC cement and primer.

Installing the Bypass Valve and Inlet Connection

A bypass valve lets you turn off water to the softener without shutting off water to your whole house. This is essential for maintenance and repairs. Most Rheem softeners come with a bypass valve already attached to the top of the tank. If yours does not, install a three-way ball valve on the inlet line before the softener.

Connect the inlet port (usually marked "in" or with an arrow pointing into the tank) to the water line you just cut. If you are using copper pipe, solder the connection. If you are using PVC, explore primer to both the pipe and the fitting, then explore PVC cement and push the fitting on firmly. Hold it in place for 30 seconds. Do not turn the water back on yet. Let PVC cement cure for the time specified on the can, usually 2 to 4 hours.

If your water pressure is above 80 psi, install a pressure-reducing valve on the inlet line before the softener. Screw it onto the threaded inlet port. Set it to 60 to 70 psi using the adjustment screw on top. This protects the softener's internal components from damage.

Connecting the Drain Line

The softener drains during regeneration, when it cleans the resin beads inside the tank. The drain line must run to a floor drain, laundry sink, sump pump, or outdoor drain. It cannot run to a septic system in most states without a separate tank — check your local plumbing code first. The drain line is usually a plastic tube that comes with the softener or is sold separately.

Attach the drain line to the drain port on the softener (usually marked "drain" or with an arrow pointing out). Push the tube onto the barbed fitting until it is snug. Run the line to your drain point. It does not need to be buried or hidden, but it should not create a trip hazard. If the drain is far away, you may need to run the line along the wall or through a basement joist. The line should slope downward slightly toward the drain to prevent water from pooling inside it.

Do not glue or permanently attach the drain line to the fitting. You need to be able to disconnect it for service. If the line is long or in a visible area, use clips or cable ties to find it to the wall or pipe, leaving the fitting end loose.

Connecting the Outlet and Turning Water Back On

The outlet port (marked "out" or with an arrow pointing away from the tank) connects to the rest of your house plumbing. This is where softened water flows to your taps, water heater, and appliances. Solder or cement this connection the same way you did the inlet, using the same pipe material as your existing line.

Once all connections are made and any cement has cured, slowly turn the main water shutoff valve back on. Open it a quarter turn at a time, waiting a minute between each turn. This prevents a pressure surge that could damage the softener or your pipes. Watch for leaks at every connection you made. If you see water dripping, turn the valve back off, let the line drain, and redo that connection.

Once water is flowing and there are no leaks, close the faucet you opened earlier. The softener is now connected but not yet ready to use.

Adding Salt and Running the First Regeneration Cycle

Open the brine tank (the smaller tank next to the main tank, or the top of a single-tank model) and check what type of salt your Rheem model requires. Most use pellets or crystals. Do not use rock salt — it contains too many minerals and will clog the system. Fill the brine tank about three-quarters full with the correct salt type.

Plug the softener into the electrical outlet. The control panel will light up. Set the time and date using the buttons on the panel — refer to your manual for the exact steps, as this varies by model. Most Rheem softeners have a button labeled "Regenerate" or "Regen". Press it to start the first regeneration cycle. This cycle cleans the resin beads and fills the brine tank with salt water. It usually takes 2 to 4 hours. During this time, you can still use water, but it will not be softened.

After the cycle finishes, the softener is ready to use. You should see a drop in the salt level in the brine tank. Check it weekly for the first month, then monthly after that. Refill when the salt level drops to about one-quarter full.

Testing and Troubleshooting

After the first regeneration, run water from a tap for a minute to flush any air from the lines. The water may look cloudy or slightly discolored — this is normal and will clear. Fill a glass and feel the water. It should feel slippery or soapy compared to your tap water before installation. This is the softener working.

If water is still hard, check that the softener is in service mode, not bypass mode. Look at the bypass valve — it should be in the middle position (perpendicular to the inlet and outlet ports). If it is parallel to those ports, the softener is bypassed and water is not being treated. Turn the valve to the middle position.

If water is leaking from the drain line, the line may be kinked or the fitting may not be seated properly. Disconnect the line, straighten it, and push it back onto the fitting firmly. If water is leaking from a soldered or cemented joint, you will need to cut out that section and redo the connection. Turn off the water, drain the line, and make the repair.

Frequently Asked Questions

Do I need a plumber to install a Rheem water softener?

If you have experience soldering copper pipe or working with PVC, and your water line is accessible, you can install it yourself. If your water line is buried, in a crawlspace, or if you are not comfortable cutting and joining pipes, hire a licensed plumber. A professional installation usually costs $500 to $1,500 depending on your location and plumbing setup.

Can I install the softener outside?

Rheem softeners are designed for indoor installation in a temperature-controlled space. Freezing temperatures will damage the resin beads and the control valve. If you must install it outside, build an insulated enclosure and add a heater. Most homeowners install them in basements, garages, or utility rooms instead.

What if my water line is PVC instead of copper?

You can connect a Rheem softener to PVC pipe using PVC fittings and cement. The process is the same as with copper, except you use primer and cement instead of solder and flux. Make sure all your fittings are rated for your water pressure — usually 100 psi or higher.

How often do I need to add salt?

This depends on how much water you use and how hard your water is. Most households add salt every 4 to 8 weeks. Check the brine tank monthly and refill when the salt level drops to about one-quarter full. Your Rheem manual will have a chart showing estimated salt use based on your water hardness and household size.

Can I connect the drain line to my septic system?

Most states do not allow softener drain water to go directly to a septic system because the salt can damage the bacteria that treat waste. Check your local plumbing code. If your code allows it, you may need to install a separate holding tank or run the line to a floor drain instead. When in doubt, run the drain line to a floor drain, laundry sink, or outside.