Water Softener Calculator
Enter the water hardness in grains per gallon (gpg). If you're not sure, you can get this information from your local water municipality.

Factors to Consider Water softener Sizing Chart:

  1. Water Hardness:

    • Measured in grains per gallon (gpg) or milligrams per liter (mg/L).
    • You can get this information from a water test or your local water municipality.
  2. Daily Water Usage:

    • Average per person usage is often estimated at 75-100 gallons per day in the United States.
    • Multiply per person usage by the number of people in the household.
  3. Regeneration Frequency:

    • How often the system needs to regenerate (clean itself) to continue providing soft water.
    • More frequent regenerations may mean a smaller unit could suffice, but it will work harder.

Basic Calculation:

Daily Softening Requirement=(Water Hardness×Daily Water Usage)

Using the Sizing Chart:

  • Columns: Typically, you’ll find columns labeled with various water hardness levels (e.g., 5 gpg, 10 gpg, 20 gpg, etc.).

  • Rows: Rows might be labeled with daily water usage in gallons (e.g., 200, 300, 400 gallons, etc.) or the number of people in the household.

  • Cells: Where a column and row intersect, you’ll find the recommended size of the water softener, usually indicated in cubic feet of resin or grain capacity (e.g., 30,000 grains, 40,000 grains, etc.).

Steps to Use the Chart:

  1. Determine Your Water Hardness:

    • Use a water test kit or get information from your local water provider.
  2. Calculate Daily Water Usage:

    • Multiply the average daily water usage per person by the number of people in your household.
  3. Find Your Coordinates on the Chart:

    • Locate your water hardness level on the chart’s column.
    • Find your daily water usage or household size on the chart’s row.
  4. Identify the Recommended Size:

    • Find the cell where your column and row intersect.
    • This cell should indicate the recommended water softener size for your needs.

Additional Tips:

  • Choose a Slightly Larger Size: It’s often recommended to choose a softener slightly larger than your calculated need to ensure efficiency and longevity.

  • Consider Peak Usage: Ensure the system can handle peak usage times without compromising on water quality.

  • Professional Consultation: It’s always a good idea to consult with a water treatment professional to confirm your calculations and choices.

Remember that the exact layout and information provided in a water softener sizing chart can vary between manufacturers and models, so always refer to the specific chart provided by the manufacturer or consult with a professional for accurate sizing.

 

 

Number of people in the house

Hardness in Grains Per Gallon 1 to 2 people* 3 to 4 people* 5 to 6 people* 7 to 8 people*
0-10 GPG 16,000 Grain 24,000 Grain 32,000 Grain 40,000 Grain
11-20 GPG 24,000 Grain 32,000 Grain 40,000 Grain 48,000 Grain
21-30 GPG 32,000 Grain 40,000 Grain 48,000 Grain 64,000 Grain
31-40 GPG 40,000 Grain 48,000 Grain 64,000 Grain 80,000 Grain
41-50 GPG 64,000 Grain 80,000 Grain 96,000 Grain 110,000 Grain
51-75 GPG 64,000 Grain 80,000 Grain 110,000 Grain 110,000 Grain
76-100 GPG 80,000 Grain 96,000 Grain 110,000 Grain

110,000 Grain

Water Hardness Scale
Grains/Gal mg/L or PPM Classification
Less than 1 Less than 17.1 Soft
1-3.5 17.1-60 Slightly Hard
3.5-7 60-120 Moderate Hard
7-10 120-180 Hard
Over 10 Over 180 Very Hard
1 gpg = 17.1 mg/L = 17.1 ppm

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