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Water Softener Grain Chart & Calculator: Ultimate Cheatsheet

Water Softener Grain Chart

Getting a water softener isn’t enough! You need to get a proper water softener sizing based on the following:

  • Your incoming water hardness
  • Your daily water usage based on family size

Undersized softeners won’t give you enough soft water to drink, and oversized softeners will burn a hole in your pocket!

But worry not; we’ve made a simple water softener grain chart and softener size calculator based on all the important factors to help you get the right size water softener for your house.

🤔How Many Grain Water Softener Do I Need?

Check the water softener sizing chart below to determine the proper water softener based on your hardness (in grains per gallon) and number of people in your house:

Water Softener Sizing Chart

Hardness in GPG = Hardness in PPM/17.1

It is assumed that a softener regenerates every 3 days (which is normal)

It is assumed that the average water consumption is 70 gallons/person/day as per EPA Water Sense estimates.

We’ve assumed common water softener sizes available as:

  • 24K grains
  • 32K grains
  • 48K grains
  • 64K grains
  • 80K grains
  • 96K grains
  • 110K grains

For ^123, the softener needs to REGEN quicker than 3 days, or a dual tank softener is needed as the hardness is too high.

🤨How Do I Know What Grain Water Softener I Need?

How Do I know what Grain Water Softener Do I need

To calculate and determine the correct water softener size for your household, you may use this formula:

Water Softener Capacity Requirement = Average Daily Water Consumption x Water Hardness (grains per gallon) x 3 (REGEN frequency in days) 

Let’s discuss the formula terms in a bit of detail:

  • Water Hardness And Iron Concentration – The concentration of hard water minerals (like calcium and magnesium) and iron in water makes cooking and laundry a nightmare.

    Hence, the higher the concentration of these minerals in your water, the higher the softener capacity you need.

    To check the concentration of hardness minerals, refer to the Consumer Confidence Report or go for the tap score hard water test
  • Daily Water Consumption – This is the water your family consumes daily, including cooking, drinking, laundry, etc. The water consumption depends on the following:
  • Number of family members
  • Number of appliances and how often do you use them, etc.


To calculate how much water you use daily, you may either refer to your city water bill or multiply the number of people living in your house by 75 (Average amount of water in gallons consumed by one person as estimated by EPA). 

  • Water Softener Sizes Available – To optimize the correct size according to your need, you may have to consider various aspects like hardness level, number of family members, etc. However, common sizes are: 24k, 32k, 40k, 64k, 80k, 96k, 110k. 
  • Water Softener Efficiency And REGEN Frequency – The size of the water softeners is also optimized by considering how efficient your softener is and the frequency of its REGEN cycle. The efficiency of a water softener depends on the grain capacity. The higher the grain capacity, the lower the frequency of REGEN, and the higher the efficiency of the water softener.
Also Read: How To Program Water Hardness Setting

🧮Water Softener Grains Calculator

Water Softener Size Calculator

Let’s take an example to understand how to use the formula to size your softener properly:

Water Softener Capacity Requirement = Average Daily Water Consumption x Water Hardness (grains per gallon) x 3 (REGEN frequency in days) 

Assuming that your drinking water has 10 GPG of hardness, household consumption per day is 225 gallons and regenerates once every 3 days.

Hence formula becomes,

Water Softener Capacity Requirement = 225 x 10 x 3 = 6,750

So, for a 6,750 grain requirement, one can go for 24,000 grain of capacity softeners, which would work sufficiently.

Also Read: Do I Need A Water Softener With City Water?

💡Water Softener Grain Chart: FAQs

What does water softener grain capacity mean?

Water softener grain capacity is the total amount of minerals that can be removed from the softener system before regeneration.

Hence, the higher the grain capacity, the higher the capacity of the water softener system to soften hard water.

What is the difference between 48,000-grain and 64,000-grain water softeners?

The one with a higher grain is more efficient in removing hard water than the one with a lower grain.

Hence, a water softener with 64000 grains can remove more hard water than a 48,000 grain softener.

However, there are other factors that affect efficiency, such as the amount of salt used.

What size water softener is for families of 2,4 and 5?

Assuming that your water hardness is 10 GPG and average water usage is 75 gallons per day, a household with 2 members needs a water softener of grain capacity of 24k to soften water properly.

Families of 4 or above need around 32k units of grain-capacity water softener to meet their daily soft water needs.

Is the higher the grain better in a water softener? 

The higher the grain capacity, the higher the softening capacity of the system to soften hard water. 

Hence, getting an oversized softener isn’t harmful but costs more money to purchase and has an undue impact on water pressure.

On the contrary, water treatment with an undersized unit would generate less soft water and regenerate frequently, defeating the purpose of buying a softener.

So, size your water softener appropriately using our chart, table, and calculator above.

How many grains of hardness should I set in my water softener?

According to the thumb rule, take hardness around 7-10 GPG to the water test to ensure your softener works properly according to your needs.

However, the exact formula for the hardness setting is as follows:

Hardness in GPG + (4 x iron in ppm) + (6 x manganese in ppm) + 2 GPG Buffer (considering softener age and unusual usage).

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