What Should a Water Softener Be Set To in Indianapolis?

You're in the basement of your Indianapolis house, the new softener is plugged in, and the screen wants a hardness number. Your water softener hardness setting in Indianapolis starts at about 19 on Citizens water. That's the utility's average, in grains per gallon. Softener makers say to match your own water, and Westfield starts near 22.

Grains per gallon, or gpg, is the unit a softener uses for hardness. Higher means harder. The number can shift from one address to the next, so treat this table as a place to start, then ask your utility for yours.

Find your town:

Sources: Citizens' 2025 report, Carmel Utilities' 2025 report and the Town of Zionsville's utilities page.

This guide is about the setting. For the full story on each town's water, and what scale does inside your appliances, see how hard the water is in Indianapolis.

What should I set my water softener at for hardness?

Set it to your water's hardness in grains per gallon. That's the makers' rule, and it's a short one. Citizens' own report calls grains per gallon "the measure often referred to in determining water softener settings."

GE's softener manual says the number on the screen should be the same as the real hardness of your water supply. The manual for Whirlpool's WHES20 and WHES30 softeners works from the same number. So on Citizens water, with nothing else going on, you'd start at about 19.

Read the exact wording

"Be sure the number shown is the same as the actual grains per gallon hardness of your water supply."

From GE Appliances, Water Softening System Owner's Manual

Those are two manuals, not every softener. Read your own first. If it says something else, go with your manual.

Two things can push the number up: iron in the water, and the kind of salt you use.

If your water has iron

The softener makers say to add 5 to the setting for each 1 ppm of clear-water iron. Ppm means parts per million. Clear-water iron is iron that's dissolved in the water, so you can't see it in the glass.

This is the makers' rule, not a state rule or a lab standard. Both the Whirlpool and the GE manual give it, and Whirlpool works an example: water at 20 grains with 2 ppm of iron gets a setting of 30. A softener from some other maker may use a different number.

Read the exact wording

"NOTE: If your water supply contains iron, compensate for it by adding to the water hardness number. For example, assume your water is 20 gpg hard and contains 2 ppm iron. Add 5 to the hardness number for each 1 ppm of iron. In this example, you would use 30 for your hardness number."

From Whirlpool WHES20 and WHES30 softener manual (Whirlpool Water Solutions)

GE's manual says the same thing in its own words. It also says its softener won't take out two other kinds, called ferric iron and bacterial iron.

Read the exact wording

"When using the softener to reduce Ferrous (clear water) iron, add 5 grains to the hardness setting for every 1 ppm of Ferrous (clear water) iron."

From GE Appliances, Water Softening System Owner's Manual

On city water here, it barely matters. Citizens' 2025 report found no iron in Indianapolis water and an average of 0.11 ppm in Westfield. Carmel's averaged 0.04. By the makers' rule, Westfield's average adds about half a grain, and Carmel's adds almost nothing. If you're on a well, test it.

If you use potassium salt

Whirlpool's manual says to raise the setting by 25% if you fill the tank with potassium chloride in place of regular salt, which is sodium chloride. The bag will say which one you have. On 19-grain water, that takes the setting from 19 to about 24.

Read the exact wording

"NOTE: If you use potassium chloride (KCl) salt instead of sodium chloride (NaCl) salt in this softener, increase the hardness setting by 25%."

From Whirlpool WHES20 and WHES30 softener manual (Whirlpool Water Solutions)

The math, worked out

Here's the makers' rule with real numbers:

• Indianapolis water at the Citizens average, no iron, regular salt: set it to 19.
• If a test showed 1 ppm of clear-water iron in that water: 19 plus 5 is 24.
• Whirlpool's own example, 20 grains with 2 ppm of iron: 20 plus 10 is 30.
• Westfield water at the Citizens Westfield average, no iron, regular salt: set it to 22.

Check your setting now

You don't need tools for this.

1. Read the screen. Find the hardness number your softener is set to now.
2. Get your water's number. Citizens customers can call 317-924-3311 and ask for the typical hardness at their address.
3. Look at the salt bag. Is it sodium chloride or potassium chloride?
4. Compare. If the screen and your water's number are far apart, open your manual to the hardness setting page.

What is the water hardness level in Indianapolis?

About 19 grains per gallon on average, in the 2025 water report by Citizens Energy Group, which runs the water in Indianapolis, and the same report shows a range from 8.7 up to 27. That's why the call to Citizens is worth making.

The town-by-town numbers, and the reason the water here is so hard, are in how hard is the water in Indianapolis.

Is 17 gpg considered hard water?

Yes. It's very hard. North Dakota State University Extension calls water hard at 7.0 to 10.5 grains per gallon, and very hard above 10.5. Our guide on how hard the water is in Indianapolis sets 17 against the U.S. Geological Survey's scale as well.

For your softener, the answer is simple. If your water tests at 17, the makers' rule says to set it to 17.

What is the ideal water hardness range for a water softener?

The two manuals we read give no ideal range for the setting. The makers' rule is a match. The number on the screen should equal your water's hardness, plus whatever your manual adds for iron or for potassium salt.

The manuals do list the hardest water each model can take. Whirlpool's WHES20 handles up to 50 grains and its WHES30 up to 95. GE's PNPR45W, PNPR55W and PNMD45W handle up to 165. Water in Indianapolis, Carmel and Westfield is far under all of these.

Where your dishwasher comes in

One dishwasher maker does draw a line. Bosch's manual for its SHX9PCL5N dishwasher says water above 9 °E has to be softened so the machine isn't damaged. It allows one other way: a combined detergent with a salt stand-in, up to 26 °E, about 22 grains. The °E stands for Clarke degrees, one more unit of hardness, and by our math 9 of them is about 7.5 grains per gallon.

Read where Bosch says it, though. The line is in the part of the manual about the dishwasher's own built-in softener and the special salt that goes in it, so Bosch is telling the owner to use that, not to soften the whole house.

Read the exact wording

"To avoid damage to the appliance, water with a hardness above 9 °E must be softened."

From Bosch dishwasher use and care manual, model SHX9PCL5N

That's one manual, for a model with its own softener built in. Whirlpool draws its own line: its dishwasher help page says water at 15 grains or more "can damage your dishwasher," and it recommends a water softener. Indianapolis water, at about 19, is past that line.

Citizens' average of about 19 grains is about 23 °E. That's above Bosch's 9 °E line and inside its 26 °E limit. Westfield's water sits right at that limit.

Notes that help the tech

If the dishwasher or washer is already acting up, write these down before you call.

• Your water's hardness: the number from your utility.
• Your softener's setting: the number on the screen, and the kind of salt in the tank.
• The softener itself: the brand, and when it was last serviced.
• The appliance: which one, about how old it is, and what you see.

Here's how repair calls work on this site.