How Much Salt Does a Water Softener Use?

By Rehan Iqbal

Most water softeners use salt to remove hard minerals like calcium and magnesium. This is a very effective and affordable way to soften the water you use in your home. For a water softener to function optimally, it needs enough salt to keep removing the unwanted hard minerals.

Water softener maintenance mostly comes down to one important task, ensuring that it has enough salt. This raises a very important question: How much salt does a water softener use? Salt consumption for a water softener depends on how much water you use and the hardness of your water. This could be anything from 20 to 80 pounds per month. On average, most homes use around 40 pounds of salt for their water softeners.

How Much Salt Does a Water Softener Need?

There are several factors that will affect how much salt your water softener will use:

The hardness of your water – in some areas, water has more hard minerals than others.
The amount of water you use – the resin needs to be regenerated according to water usage.
The quality of the salt you use – some types of salt are more effective than others.
The efficiency of your water softener

Calculating Salt How Much Salt to Use for A Water Softener

If you want to accurately determine how much salt a water softener uses, you should multiply the number of days between regeneration cycles by the gallons of water used per day. Multiply this number by the hardness of your water in parts per million (PPM).

An older water softener will use more salt than a new one. If your water softener is more than ten years old, you will probably need to add more salt and do so more regularly.

How Often Should You Add Salt to Your Water Softener?

Because the size and efficiency of water softeners vary, as does our water consumption and the type of salt we use, determining when to put salt into your brine tank is something we need to monitor. When you first install a water softener, you may check your salt level more often than you need to. As you become accustomed to the amount of salt you use, you will develop a habit of checking it in accordance with the amount of salt you use.

A general recommendation is to check the salt once a month. At the end of every month, inspect your brine tank and check if the salt level is correct according to your owner’s manual. Typically, most homes require 40 to 50 LBS of salt per month.

How Do I Know if My Water Softener Needs Salt?

The best way to establish if your water softener needs salt is to check the brine tank. Open the tank and look inside. It should be about half full to function optimally. Add enough salt so that about 50% of the tank volume is filled with salt.

If you notice signs of hard water, you should also check the brine tank to see if it has enough salt. These would include:

A white residue on your faucets.
Bathtubs, sinks, and showers will accumulate a white chalky film.
White spots on your clothing after washing.
A white film on dishes.

What Happens if Your Water Softener Runs Out of Salt?

Since salt is essential to a well-functioning water softener, it is essential to ensure that your brine tank always has sufficient salt. When the salt runs out, the resin becomes saturated with hard minerals and the ion exchange ceases. In other words, your water will no longer be softened.

There are several consequences that result from having no salt in your water softener:

Water pipes can become blocked by accumulating limescale.
The control valve for your water softener may stop functioning. Buildup of calcium will prevent the valve piston from moving freely.
Water heaters will be less efficient.
White residue will accumulate on clothing, plumbing fixtures, and dishes.
Soap won’t lather properly.

Water Softener Maintenance Tips

In most areas, a water softener is an essential part of your household plumbing system. To ensure that it functions at optimum capacity, you need to keep it in tip-top condition. This requires some simple regular maintenance.

By following these basic water softener maintenance guidelines, you can be assured that your water will be free of hard minerals and your water softening system will last a long time.

Check Salt Level

As we’ve established, salt is the most important aspect of a water softener. Check the salt in your brine tank regularly. Generally, once per month is recommended. Ensure that the brine tank contains around 50% salt. Using high-quality salt will provide the best softening and prevent unnecessary additional maintenance.

Keep Your Brine Tank Clean

Using quality salt will reduce the accumulation of sediment and the formation of salt clumps. However, you should clean the brine tank and control valve at least once a year. To do this, you need to remove the brine tank and empty its contents, then clean it with bleach and rinse with clean water. Disassemble the control valve and clean it.

Prevent Salt Bridges

The salt in your brine tank can form a hard crust, known as a salt bridge. This prevents the salt from dissolving to create the brine needed to regenerate the resin. Check for salt bridges and break them up when they occur.

If you notice that salt bridges form regularly, have your water softener inspected by a professional to determine the cause.

Replace Water Softener Resin

Water softener resin is designed to last about 15-years which is the expected lifetime of a water softener. This means that you probably won’t have to replace the resin as part of your regular maintenance regime. However, some factors, like excessive chlorine in your water, may cause the resin to degrade prematurely.

There are two obvious signs that you may need to replace your water softener resin:

Water does not soften even when there is enough salt.
You notice small particles, known as fines, in your water.

If you notice that the resin bed needs replacing, consult your owner’s manual or call a professional water softener technician.

Why Does a Water Softener Need Salt?

Hard water is result of dissolved hard minerals, like calcium and magnesium. These minerals are positively charged, meaning that they have more protons than electrons. Calcium has 20 protons for every 18 electrons, making it 2+. Sodium in salt (NaCl) is negatively charged. This means that a brine of dissolved salt will attract hard minerals, in a process known as ion exchange.

A water softener has two tanks, an ion exchange tank, and a brine tank. The ion exchange tank is filled with resin beads that are covered with sodium (Na). As the hard water passes over these beads, the hard metals are extracted by clinging to the negative beads. Once the beads become saturated with hard minerals, they need to be regenerated by flushing the tank with salty water from the brine tank. For the process to work effectively, the brine tank needs enough salt at all times.

Types of Salt Used for a Water Softener

While some water softener salt brands may be purer than others, there are three basic types of salt that you can use:

Crystals: Often leaves a residue in the tank that needs to be cleaned, thereby increasing your maintenance.
Pellets: The most recommended for high efficiency and low maintenance.
Block: not very common for water softeners.

You also need to consider the purity of the salt. There three methods of processing salt:

Rock Salt: The lowest quality salt, with impurities like calcium sulfate. Rock salt does not dissolve as easily as other types.
Solar Salt: Made from evaporated sea water and is 99.6% pure. It is not the best for extremely hard water.
Evaporated Salt: The purest type of salt (at least 99,9%). This is the most effective salt for water softening and is also used for human consumption (table salt).

Water Softener Efficiency

Your water softener will have settings so that you can adjust the efficiency, according to how much salt you want to use. Using less salt will be more efficient in terms of salt consumption but may not soften the water entirely, especially if your water is particularly hard.

Water softener settings:

Low: Best efficiency, using the least amount of salt. You can use this setting for water that is slightly to moderately hard.
Medium: Average efficiency for moderately hard to hard water.
High: Least efficient, using the most salt. This setting is best for hard to extremely hard water.

Water Hardness

The hardness of your water is determined by how much calcium and magnesium is in the water. This is expressed as the amount of calcium carbonate which is measured in milligrams per liter of water (mg/L). A high concentration of calcium carbonate per liter will result in harder water. Water hardness can also be measured as grains per gallon (GPG)

You can determine the hardness of water as follows:

Soft Water: Less than 75 mg/L or less than 3 GPG
Moderately Hard Water: 76 to 150 mg/L or 3 to 7 GPG
Hard Water: 151 to 300 mg/L or 7 to 14 GPG
Exceptionally Hard Water: More than 300 mg/L or more than 14 GPG

Hard Water Areas

The best way to know for certain how hard your water is would be to have it tested in a laboratory. However, certain areas are known to have harder water.

About 85% of the US has hard water. The hardness varies in different states. Large parts of Northern USA are designated as extremely hard water areas and parts of South-Central USA and the Gulf Coast also have extremely hard water. In these areas, water hardness is more than 14 GPG. Most of Western USA has hard to very hard water (7 – 14 GPG).

Water Usage

The average person in the US uses 101.5 gallons of water per day. The average for a family is approximately 300 gallons per day.

Water usage in the home can be estimated as follows:

Bathtub: 36 gallons
Toilet: 3 gallons per flush
Shower: 2 gallons per minute – a 10-minute shower will consume about 20 gallons of water
Washing machine: 15 gallons for a load
Hygiene (washing face, brushing teeth etc.): 2.5 gallons per person
Drinking: 1 gallon per person