What Size Water Softener Do I Need?

Key Takeaways:

• Having the wrong-sized water softener can lead to increased costs and reduced efficiency.
• The proper size water softener system for your home will depend on several factors, including your household size, the water hardness level, daily water usage, and desired efficiency.
• Water hardness is measured in grain capacity (gpg), which is the amount of hardness the softener can remove before regeneration.
• Tucson has very high water hardness levels, averaging at 12-13 gpg.

You got a water softener for a reason: to soften the hard water in your home. So, you want to make sure that the system works effectively and does the job it's meant to do. When it comes to your water softener's efficiency, sizing matters a lot:

• Too small: A water softener that’s too small will regenerate too often, wasting salt and water.
• Too big: An oversized system can waste resources and increase upfront costs. You purchased a larger (and more expensive) system for no reason. And the unit won’t use the salt and water as efficiently, leading to higher salt costs and an increased water bill.

Correctly sizing your softener ensures optimal performance and efficiency. Sizing also affects water quality consistency and the system's lifespan.

Here are the key variables that go into selecting the right system:

• Household size: More people mean higher water usage and a need for a larger unit.
• Water hardness: Water hardness is measured in grains per gallon (gpg). Tucson typically has 12-13 gpg, which is considered a very high hardness level.
• Daily water usage: The average person uses about 75 gallons per day. However, if the people in your household tend to use more, this should be considered.
• Desired efficiency: Some systems are designed for fewer regenerations, saving salt and water.

When considering all these factors, a family of four in Tucson with 20 gpg hardness would need a medium-to-large

Here’s the simple calculation for finding the right water softener capacity:

1. Multiply the number of people in the home by average daily water use (average is 75 gallons).
2. Next, multiply that number by the water hardness in grains per gallon.
3. Next, multiply by 7 days to estimate the weekly softening demand.
4. Finally, divide by 1,000 to find the required grain capacity (e.g., 32,000–48,000 grains for most homes).

Note that “grain capacity” refers to the amount of hardness the softener can remove before needing regeneration. Local water reports or in-home testing can accurately determine hardness levels.