In a home, hard water is a source of concern. It creates a variety of issues, ranging from reducing the efficiency of your home’s equipment to clogging drains. The only way to solve this problem is to soften your water. You can accomplish this with the assistance of a water softener.

A water softener is a permanent solution to doing away with the hard water in your household. The hardness in water comes from water containing high concentrations of minerals like calcium and magnesium.

Water Softener Sizing Guide - water, use, softener, hardness, grains

The chemical structure of these minerals causes them to bond with other metals and surfaces. And the result is the crusty residue on your faucets and showerheads, scum, and any surface that comes in touch with hard water.

To learn more about installing your water softener the right way, visit this page.

How do you know you have hard and not soft water?

  • When your clothes become stiff after washing
  • When you get dry or irritated skin, scalp, and hair after taking a shower
  • When crust (limescale) builds/forms around your taps (faucets) and showerheads.
  • When soap scum develops on your shower walls and sinks
  • When your electric appliances like kettle develop a coating inside them.

From the examples above, you know that hard water always leaves a residue of its minerals behind. And if left, they build up over time and clog drainage systems and reduce the efficiency of water heaters, boilers, and water pipes.

As a result, it is critical that you utilize a water softener. It will remove all of the hard water components (calcium and magnesium ions), hence eliminating the harmful impacts of hard water.

How does a water softener work?

When you put water softeners in your water system, they remove all hard water minerals from the water. How do they do this?

The resin beads of the water softener are negatively charged. So as the hard water passes through the softening system, the negatively charged resin beads of the water softener attract the positive ions of calcium and magnesium. And in so doing, the hard water components of water are trapped in the resin bed of the water softening system.

So, how do you know the proper size of water softener to use?

What size water softener do I need? You can get to know the right size of water softener to use in the following steps;

Step #1: Determine the size of your water softener

Water softener comes in different capacities.

Tip: The rated capacity of a water softener is the highest number of grains of water hardness that the softener unit can remove before any regeneration.

So to get the right size of water softener, calculate the amount of water used each day in your home. The following steps will help you learn  how to size a water softener:

  • Determine the number of people in your household.
  • Determine the number of gallons of water they use daily
  • Multiply the people number by the gallons of water. This will give you the amount of water you need to soften each day.

Step #2: Determine the number of grains of hardness in your water (Calculate water softener size)

To do so, you can use a hard water test kit. If you use city water, you can contact your municipal authority for the information.

The simpler way of determining your water hardness level is to use the figures you got in step #1. This figure will clue you into the right water softening size for your household. From the amount of water your family uses each day, determine the number of grains of hardness you need to remove each day from the water.


Let’s assume that your household has 4 people who independently use 80 gallons of water each day.

Hardness = 10 grains per gallon

Daily household water consumption = 4 x 80 =320 gallons per day

Daily softening requirement = 320 gallons per day X 10 grains per gallon = 3200 grains per day

The water softener will remove 3200 grains of water hardness per day from this example.


The unit of water hardness is grains per gallon (gpg). If your water measurement is in liters (L), milligrams (mg), or parts per million (ppm), convert the figure to grains per gallon (gpg).

For clarity, 1gpg = 17.1mg/L = 17.1ppm.

Use the units above to measure the number of hard water particles in your water.

Step #3: Buy a water softener that can handle the load

Water softener sizing is according to the number of hard water grains. So, buy a water softener that can remove that hard water components daily.

Tip: A four-person household uses a 33,000-grain water softener.

Other considerations for water softeners

Water softener capacity

This is the amount of hardness a softener can remove from the water before it needs to regenerate or recharge.

What size water softener do I need? To get the right capacity of your water softener, you must consider two things;

  • The capacity of the grain system. This is the weight of the magnesium and calcium compounds that the water softener can remove before the softener becomes saturated and undergoes regeneration.
  • The size of the water softening resin. The resin bed should have the capacity of salt that is equivalent to the grain capacity of the softening system.


As time passes, the resin bed of the water softener becomes coated with the hard particles of water. When this happens, regeneration/recharging occurs. The incoming water mixes with the trapped salt and hard minerals in the regeneration cycle, leaving the resin bed clean.

Once regeneration is complete, the water softener continues providing soft water to your household.

Tip: A water softener is sized to regenerate once every week.

What is the importance of resin bead regeneration?

A water softener is made in a way that it regenerates once every week.

This is done to keep the resin bed fresh and reduce the wear and tear on the water softener valve. The valve has moving components that only move when the water softener regenerates.

So the once-a-week regeneration keeps the water consumption low, which reduces the excess burden of wear and tear on the valve.


With this water softener guide, you can efficiently take care of your softener needs. Getting a water softener with the right daily grain capacity ensures that your household enjoys a steady supply of soft water daily.