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How to Size a Water Softener

Properly Sizing a Water Softener Will Give You Soft Water for Years to Come



How to size a water softener:

To correctly size a water softener, you will need the know the following:

- Your water's hardness level (measured in grains per gallon)

- Your water's iron level


First, have a water test conducted to determine the hardness level and iron level. 


Water softeners are measured by "grains" or "grains removal"

1 Grain per gallon = 17.1 parts per million (PPM)

If your hardness results in is PPM, then just divide by 17.1 to get your Grains Per Gallon.

In the United States, the average GPG (Grains per gallon) is 10.0.  Let's use 10 GPG to determine the softener size we will need.

Multiply the # of people in house

X 80 (average no. of gallons used by person per day)

x 10 grains of hardness

Therefore, 4x80x10 = 3,200 Per Day

If Your Daily Grain Requirements Are:        You Need a Water Softener With:

0 - 3,500 Grains Per Day                                 24,000 Grain Capacity

3,501 - 4,500 Grains Per Day                          32,000 Grain Capacity

4,503- 6,850 Grains Per Day                           48,000 Grain Capacity

6,851 - 9,150 Grains Per Day                          64,000 Grain Capacity

9,151 - 11,500 Grains Per Day                        80,000 Grain Capacity


NOTE: If iron level is over 5 PPM, you will need a separate iron filter.

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