Water Softeners: The Complete Guide

A water softener takes the hardness out of your water: the calcium and magnesium that leave white scale on your faucets and build up inside your water heater. Inside the tank are small resin beads. As your water passes through, they pull the hardness out, just like a magnet, and give up a small amount of sodium in its place.

Every so often the valve on top cleans the beads with salt water from the salt tank and sends the hardness down the drain, usually at 2 AM while you are asleep. Here is each part on a real Fleck 5600SXT softener, and the guide that answers your next question.

The three parts of a water softener

A salt-based softener has three parts: a control valve on top, a resin tank under it, and a salt tank beside it.

The control valve is the part on top. It has a meter in it that counts the gallons going through the tank. From the hardness and the capacity programmed into it, it knows when the beads are nearly full and starts the cleaning cycle. On our Fleck softeners the stainless bypass valve comes already mounted on the valve, so your plumber can send water around the softener when it needs service.

The resin tank (also called the mineral tank) holds the resin beads, the part that does the softening. On the 48,000 grain Fleck, the size most people buy, that is 1.5 cubic feet of 10% crosslink resin (a sturdier grade than the standard 8%) in a 10 by 54 inch tank.

The salt tank (the brine tank) holds the salt. After each cleaning cycle the valve puts water back in it, the water dissolves some of the salt, and the next cycle draws that salt water out. Keep the salt level higher than the water level.

In this video I explain how a softener works standing beside the 64,000 grain version of this softener. The how-it-works part starts at 0:31.

How the resin beads soften your water

The resin beads catch the calcium and magnesium as your water passes over them and let go of sodium in their place, so the hardness stays in the tank and softened water goes on to the house. That trade is called ion exchange. As I put it in the video, the beads pull the hardness out just like a magnet and store it inside the tank.

Hardness is measured in grains per gallon. How to test water hardness shows how to get your number and read it.

What goes into your water in exchange is a small amount of sodium, not salt. I tell people a softener does not put salt in the water the way they think: the salt water from the salt tank is rinsed down the drain. What stays in your water is the sodium the beads traded for the hardness, and harder water means more of it. The numbers by hardness are in is salty softened water safe to drink.

How a softener cleans itself at night

When the beads are nearly full, the valve cleans them with salt water from the salt tank and sends the hardness down the drain. That cleaning cycle is called regeneration. On our Fleck softeners it usually runs at 2 AM and takes about an hour and a half. The valve counts gallons, so it regenerates when you have used up the beads, not on a calendar.

The Fleck 5600SXT runs four steps:

1. Backwash. Water runs up through the tank and out the drain. It lifts the beads and rinses out dirt and sediment.
2. Brine draw and slow rinse. The valve draws salt water from the salt tank and rinses it slowly through the beads. The sodium pushes the calcium and magnesium off, and they go down the drain.
3. Rapid rinse. Fresh water rinses the leftover salt water out of the tank.
4. Brine refill. The valve puts water back in the salt tank so salt water is ready for next time. Then the softener goes back to work.

How often it runs, how much water and salt one cycle uses, and how to start one by hand are all in water softener regeneration.

The types of water softeners

For most homes I prefer a single-tank softener with a separate salt tank. Twin-tank, cabinet and salt-free units each fit a special case.

The one thing a twin tank changes is the cleaning cycle: it switches to its second tank, so you never get hard water while the first one cleans. In most homes nobody is using water at 2 AM, so it does not matter. A metered valve like the Fleck regenerates by gallons used, which wastes less water and uses less salt than a timer. The salt-free question gets its own page: salt-free water softeners: do they actually work.

Who does not need a water softener

A softener only fixes hardness, so you do not need one if your water is under about 7 grains per gallon of hardness, and it is the wrong first fix for iron or low pH.

• Water under about 7 grains of hardness. Appliance makers recommend softening at 7 grains per gallon and above. The certified well water test gives you hardness, iron and pH from one sample ($199); on city water, the city water test.
• Iron. At low levels a softener can take some iron out, but iron shortens the life of the resin. The 48,000 grain handles up to about 1 ppm of dissolved iron; above that, an iron filter goes in first. More in can a water softener remove iron.
• Low pH. Acidic water needs an acid neutralizer. Its calcite raises the pH and adds about 3 to 6 grains of hardness, which is why a softener often goes in after it. See acid neutralizer and water softener: do you need both.
• A rotten egg smell. That is a different problem. Does a water softener remove sulfur smell explains what does.
• Chlorine taste on city water. That is a carbon filter's job. See carbon filter and water softener: do you need both.

Where a softener goes with other equipment

The softener usually goes last in line among the treatment tanks: after the well tank, the sediment filter and any iron filter your test calls for. On city water it goes where the water comes into the house. If your pH is low, an acid neutralizer goes in too, and I set its place from your test. A UV light, if your test calls for one, goes after the softener. The whole lineup is in the correct order for well water treatment systems.

A caller in September had 17 grains of hardness and 2 ppm of iron with three or four people in the house. I told him to put a 1.5 cubic foot iron filter first and the 48,000 grain softener second, because iron weakens the softener resin over time and shortens its life.

Have your water test results?

Text me your water test

Send a photo of your hardness and iron numbers. I will tell you whether you need a softener, what size, and what goes ahead of it.

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 downsides of a water softener

The real downsides are that you keep buying salt, it needs a drain and an outlet, each cleaning cycle sends water down the drain, and it adds a small amount of sodium to your water.

• Salt. Plain pellets are about $8 for a 40 lb bag. For most homes that is 8 dollars a month, maybe 16 if you use a lot of water. Which salt to buy is in water softener salt.
• A drain and an outlet. The valve plugs into a standard outlet, and the cleaning cycle needs a floor drain, utility sink or standpipe within about 20 feet for 1/2 inch drain tubing. Drain tubing is not included.
• Water for each cycle. The gallons and salt one cycle uses, by size, are in water softener regeneration.
• Sodium. It adds a small amount, more on harder water.
• A plumber. Every tank ships empty, with the resin in separate bags that are loaded into the tank at install. We recommend a licensed plumber; a licensed plumber typically completes the install in 2 to 3 hours, and I tell callers to expect about $700 to $1,000 for it. I support your plumber by phone at 800-460-5810.

Which guide answers your next question

Each of these questions has its own guide, so the answer is in one place.

Frequently asked questions