What Hardness Level to Set Your Water Softener

Set the Softener to Your Actual Hardness

Set the water softener hardness level to match the measured hardness of your incoming water, typically expressed in grains per gallon (gpg) or parts per million (ppm). The softener regenerates based on this number, so an incorrect setting wastes salt, wastes water, or leaves scale in the pipes.

How to Find Your Water Hardness

Use a test kit, a municipal water report, or a lab test. Test strips give a quick estimate, but a drop-test kit or lab analysis is more reliable for setting a softener.

• Municipal report: look for total hardness in gpg or mg/L (ppm).
• Home test kit: follow the kit instructions and record the result in gpg.
• Lab test: mail a sample and ask for hardness in gpg.

Converting Units and Setting the Valve

If your test result is in ppm or mg/L, divide by 17.1 to get gpg. Enter that number as the hardness setting on the control valve. Most softeners are pre-set around 7 to 10 gpg, which is a common municipal level, but local water varies widely.

What Happens If the Setting Is Wrong

Setting the hardness too low causes the softener to regenerate too often, wasting salt and water. Setting it too high leaves hard water untreated, so scale builds up on fixtures, inside pipes, and in water heaters.

Special Cases and Adjustments

If you have very soft water from a well or rainwater system, you may not need a softener at all. Iron, manganese, or high TDS can also affect how the softener performs and may require a pre-filter or a different resin type.

Final Check

After setting the hardness, run the softener through one full cycle and test the softened water with a conductivity meter or soap test. If soap still does not lather easily or the water feels slick, re-test the incoming hardness and adjust the setting.