Category: System Recommendations

Sizing a Water Softener

What size of softener do I need?

Water softeners are sized according to the grain capacity they are capable of removing between regenerations. A 48k or 48,000 grain system is capable of removing 48,000 grains of hardness between regenerations based on standard regeneration settings. To properly size a softener you will at minimum need to know your hardness level. If you are using an all-in-one system to treat iron and manganese you will need to know those levels as well. Knowing your typical water usage in gallons per month/week/day will also help get the most accurate recommendation, but averages can be used for that. Once you have that information follow the steps below to help determine what size of system you need. If you print this page off you can use the space to fill it out as you go.


Step 1
Determine water hardness level.

Start with your water hardness (may be listed as CaCO3 on your water report). You will need the grains per gallon (GPG) level for these calculations. If your test shows parts per million (ppm) or milligrams per liter (mg/L) divide that by 17.1 to get the grains per gallon. (Round up to the nearest whole number for best results.)


Step 2
Compensate for iron/manganese (if applicable).

If you have any iron or manganese (not to be confused with magnesium) in the water, add both of those together (in ppm or mg/l) and multiply by 4. Add that to the hardness from above to get your total compensated hardness. (Round up to the nearest whole number for best results.) If you do not have any iron or manganese enter 0 in that field, and your compensated hardness will be the same as your hardness above.


Step 3
Determine water usage (in gallons).

Determine how much water you use on average every day. You can either estimate your usage based on the number of people in the house, or you can take and divide the number of gallons used in a month as shown on a water bill or water meter. If you are unsure it is best to assume average water use for the number of people there the majority of the time. Our on demand softeners will adjust as necessary if there are more or less people than normal, but sizing should be made for normal circumstances to ensure the best results.


Step 4
Calculate daily and system grain requirements.

Using the information calculated above, multiply your water usage (estimated or average) by your total compensated hardness. This will provide the average daily grains of hardness that you need to treat. Multiply that number by the number of days between regenereation desired to get your ideal grain capacity. With iron or manganese in the water 3-7 days is common (minimum of every 7 is recommended to prevent resin fouling). Water without iron or manganese are typically sized to go 7-14 days. Once you have your ideal grain capacity you can use it to find the system that most closely matches it.



In most cases the system sizing recommended in this link will be adequate for most homes. If you have low hardness and/or a high flow rate (in gallons per minute) you may need to get a larger than recomended system to keep up with higher flow rate demand. Be sure to look at system service flow rates to ensure they meet your needs. If your ideal grain capacity is larger than our standard systems even using 3 days between regenerations you will want to use a dual tank system. You can also use a dual tank system if you want higher efficiency.

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Abundant Flow Water
2261 Schoenchen Rd
Pfeifer, KS 67660

Phone: 785-735-9769

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