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How to Size a Water Softener

How to Size a Water Softener Properly?

Proper Water Softener Size does matter! There are lots of water softener sizes are available in the market. If you select a small sized filter for whole house, it will not fulfill your everyday demand. Furthermore, if the water softener is too small, it'll drop softening capacity, minimize water pressure, and require frequent servicing.

On the other hand, no need to spend extra money buying extra large softener. Too large softeners are expensive, and an irregular regeneration cycle can damage its resin bed.

To buying proper sized kit, you need to know how to size a water softener properly. As it depends on many factors.

The adequately sized water softener can maintain a continuous flow of clean water in a household.

In this article, we will go through step by step guideline to determine proper size water softener. The first step is understanding the regeneration efficiency and grain capacity. Let's move on...

Last update on 2023-02-16 / Affiliate links / Images from Amazon Product Advertising API

A water softener that uses excessive salt will likely have a small grain capacity. It is not supposed to regenerate every three days or last for 15 days without regeneration. There should be a balance in between.

Sometimes you get a correct sized water softener, yet it has vast salt consumption. Ever thought, why this happens?

The reason is that most seller doesn't understand the concept of salt efficiency.

The capacity of water softener determines the amount of salt to include and how much will get discharged. Considering the salt efficiency ensure that you get a softener that never runs out of soft water.

With the proper efficiency, a water softener uses a minimal amount of salt. Over the period, it guarantees vast cost savings, longevity, and ease of maintenance.

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How to Size a Water Softener?

The size of a water softener should be efficient enough to meet the requirement of your family. Sizing is all about matching your water consumption and water quality with a sized system.

It should be capable of reducing salt use and boosts soft water capacity.

You can also Check This Link to buy an inline water filter as it does a similar job.

Several factors involve determining the size of the water softener. We'll discuss them in detail so you can quickly size your water softener.

1. Water Hardness Level

Knowing the exact hardness level in your water is crucial. It relates to your daily softening necessity, which means how much hardness the softener has to remove. There may be magnesium and calcium dissolved in every household water.

If you are using the water for drinking, you can have a Brita pitcher in your household.

Learn the Best Way to Clean Brita Pitcher here.

A water softener can also do the job. Water is classified as "soft," "moderately hard," and "hard," depending on the hardness level.

Hardness level can measure in either PPM (parts per million), mg/L (milligram per liter), or GPG (grains per gallon).

Here GPG is the industry standard way to calculate hardness level.

To convert from PPM or mg/L to GPG, you need to divide PPM or mg/L by 17.12.

It is essential to know the exact water hardness level while programming your softener. The system will ask for the hardness value.

How to learn the hardness value you are dealing with it?

Well, there are a couple of ways:

1. There is a range of test kits available online with a fee of cost. You can test the calcium and magnesium levels yourself.

2. You can also test in the local laboratory.

3. Ask for a Quality Report From the Supplier

Moreover, keep the high iron levels in mind, especially you are consuming well water. Here you can also install the Best Iron Filter System for Well Water.

However, add 4 GPG to the total hardness level for each 1mg/L or ppm of iron. Some expert suggests adding 3 GPG.

For example, consider hardness level 140 mg/L and iron level 1mg/L.

As mentioned, 140mg/L / 17.12 = 8.18 GPG.

Total hardness level= 8.18 GPG + 4 GPG= 12.18 GPG.

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2. Water Consumption

The next thing to consider is your household water consumption. You can get an idea from your recent water bill. The bill displays the use of water for a certain period, such as a month, quarterly, or yearly.

This data is needed to determine water consumption per day. In case you cannot access this data, then multiply the number of people in your family by 75 gallons. You'll get an estimated value of the daily water use.

Say, you have four members in your household.

Daily water consumption: 4 member x 75 gallons= 300 gallons/day

3. Daily Water Softening Requirement

Once you learn the daily water consumption value, you can calculate the daily softening requirement. Here you'll need the hardness level.

Note that, hardness level= 10 grains/gallon.

Daily Water Softening Requirement: hardness level x daily water consumption = 10 grains/gallon x 300 gallons/ day = 3000 gallons/day.

It means the water softener should be capable of removing 3000 grains/day. The softener needs to regenerate once per week.

4. Total Grain Capacity

A water softener removes loads of grains before it requires to regenerate. However, this also determines how the softener works. After many days of use, the resin bed inside cannot bind magnesium ions and calcium ions.

Regeneration comprises washing out the gathered minerals and boosting the resin bed with potassium or sodium. Generally, it is better to regenerate the softener in each week.

Grain Capacity

Grain Capacity

Thus, the softener produces minimal wastewater, provides better-softening efficiency, and protects the head valve. The resin bed stays protected against sediment and iron.

Mentioning that your softener regenerates every 7 days, you can determine the total grain capacity.

Total grain or softening capacity: daily softening requirement x 7 days = 3000 grains/day x 7 days = 21000 grains/week.

5. Salt Efficiency

Thus far, we've learned that you need to regenerate a softener with 21000 grains/week ratings. Therefore, the softener will never run out of water.

Earlier, we mentioned, a water softener requires a certain amount of salt, so we need to consider salt efficiency. A softener requires lots of salt to regenerate the resin bed completely.

But, partial regeneration has also proven to be more productive. A water softener will likely require 14.1lbs of salt to regenerate a 33000-grain system fully.

The same system requires 2.6lbs to restore the 13000-grain unit.

Simply put, a 33000-grain system can eliminate 33000 hardness grain in two regeneration cycles. But, it may demand too much salt. The higher salt dose ensures higher softening capacity, though the low efficiency/lbs. of salt.

It is a smart choice to pick higher grain capacity than the total exactly calculated grain capacity.

For instance, choose a 40000-grain system to remove 21000 grains/week. So it does partial regeneration and saves money on salt.

Moreover, this also ensures convenient servicing and even the less amount of salt release to the environment. Having a Berkey filter alongside can increase the efficiency of the water softener. You can learn about Berkey Filter Cleaning Process from here.

6. Look at the Maximum Grain Capacity Concerning the Resin Size

  • 0.75 cubic feet of resin – 15000-grain capacity.
  • 1 cubic foot – 20000-grain capacity.
  • 1.5 cubic feet – 30000-grain capacity.
  • 2 cubic feet – 40000-grain capacity.
  • 2.5 cubic feet – 50000-grain capacity.
  • 3 cubic feet – 60000-grain capacity.

The best option to choose a water softener with 1-cubic feet resin. Because, it requires= 20000 grains/3000= 6.7 days or close to 7 days between regeneration.

Grain Capacity Concerning Resin Size to Understand Water Softener Size

7. Consider Water Flow Rates

At a time, your household can have too many faucets running. Especially in the morning, when everyone uses water to get ready for the day. There may be multiple showers running in your bathroom, kitchen, dishwasher, etc.

Some people use alkaline water pitcher to have filtered water for consumption.

Find some of the Best Alkaline Water Pitchers to buy from here.

All these affect the water flow rate, which is measured in gallon per minute.

Determine Water Flow Rates to Understand Water Softener Rates

Determine Water Flow Rates to Understand Water Softener Rates

The larger family requires a higher water flow rate of at least 15 gallons/minute.

Equally, a smaller family should be ok with 6 or 7 gallons/minute. More things affect the water flow rate, such as; bypass valve, mineral tank, and distribution system.

Last update on 2023-02-16 / Affiliate links / Images from Amazon Product Advertising API


At this point, you know about the variables that require in sizing a water softener. Calculate the values for your corresponding water consumption.

Also, determine the regeneration frequency to keep your water softener in a better state.

The best water softener is supposed to boost softening capacity, but minimize water and salt usage. Make sure your water softener does the same.

So, this is how to size a water softener; let's give it a try!

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