Finding the Right Water Softening Sizing System
Before you select a water softening system for your home, there are a few things you need to do that will help ensure you choose the right water softening system for your needs. You’ll need to test the water for its hardness, determine your household’s daily water usage as it relates to the number of people living in the home and calculate the needed capacity.
Water Softener Sizing Chart
Water softeners are classified based on grain capacity. It shows how many minerals that cause hardness can be removed. Water softeners remove minerals causing hardness from tap water. They eventually need to drain all the minerals that they have collected. The process of draining out those minerals is known as a regeneration cycle. A larger number indicates that more hardness is treated between regenerations.
How to Determine the Appropriate Water Softener Grain Size
Knowing the water hardness level will help determine which water softener you need. Follow these steps to choose the correct softener.
1. Test the Hardness Level of the Water
To determine the hardness of your water, purchase a test kit or contact your water provider. The test kit will help you determine the grains per gallon (gpg) hardness level.
If your water has extremely high levels of hardness or contaminants like iron, consult a water specialist.
2. Calculate Your Household’s Daily Water Use
You want to determine the amount of water that’s required for the household per day. To do this, count the number of people in the house and multiply that by the average daily use of water per person, typically 75 to 80 gallons.
Example: 4 people x 80 = 320 gallons/day.
3. Determine the Daily Hardness Load
Multiply your water hardness (gpg) by the number of gallons used per day.
Example: If hardness is 15 gpg and you use 320 gallons/day:
- 15 x 320 = 4,800 grains/day - you need a system that can remove 4,800 grains per day.
4. Factor in Iron, If Necessary
If the presence of iron is in your water, this must be factored into the hardness load.
Add 3-5 gpg for every 1 ppm of iron (1 gpg = 17.1 ppm) when doing your calculations.
What Grain Size Water Softener Do You Need?
Determine if the softener can meet the average and peak demand before it requires recharging. Correctly estimating this will ensure the softener's long life. This step will, however, require some trial and error before settling on the correct choice. If you have a rough estimation of your peak and average water use, you can refer to the water softener’s manual, as it’ll have all the details regarding its usage.
Determining the right size for your softener involves making a few guesstimates about the nature and water consumption in your home. It’s better to overestimate capacity than to choose a system that’s too small. A quality softener with the right capacity will effectively remove the hardness required under heavy usage. You will want a softener that covers your weekly needs without regenerating too often. Use the example from above of your daily grains x 7.
- Example: 4,800 x 7 = 33,600 grains per week
- Softeners are sold as grain capacity units – 24,000, 32,000, 40,000, 48,000, etc. A 40,000-grain unit would be the next level up unit and would work.
To estimate the right size, use the steps and the chart provided in this guide as a great starting point. A well-designed system with the correct softener grain size will properly treat the water. When you want to do a bit more research, we have a guide to tell you a bit more about the different types of water softeners for your home.
Normal water usage accounts for an average of 80 gallons per day per person. If there is frequent water usage outside the norm for activities including watering the lawn, washing cars, laundry, etc., factor this into a larger water softener grain size.
Guiding You to the Right Water Softener
Deciding to purchase a water softener is an important one that requires forethought and a bit of homework before jumping in and making a purchase. Once you’ve done the homework, made all your calculations and you’re ready to go, we have a large selection of water softener systems from which to choose. Shop online at Lowes.com or stop by your local Lowe’s and a Lowe’s Red Vest associate will be happy to walk you through our in-store selection and more.