Free Interactive Tool
Water Hardness Calculator
Enter your hardness reading to see what it's costing you annually — and what it's doing to your appliances.
Enter Your Hardness
gpg
0 gpg (Soft)10 gpg (Hard)20 gpg (Extreme)
Unit Conversions
Grains/gallon
12 gpg
Milligrams/liter
205.4 mg/L
Parts per million
205.4 ppm
French degrees
20.5 °f
Very Hard10.5–14 gpg
Rapid scale on all appliances. Tankless heaters at risk. Skin and hair noticeably affected.
Softener urgent — appliance damage accelerating
Hardness Severity
SoftModerateHardVery HardExtreme
Estimated Annual Hard Water Cost
Soap & cleaning products
$756/yr
Energy waste (scale)
$45/yr
Appliance repair/replacement
$285/yr
Total annual cost
$1,086
Potential annual savings with softener
$576
Appliance Damage Timeline at 12 gpg
5
Shower heads & faucets
Visible scale buildup, reduced flow
$50–$200 to replace
~5 months without treatment
8
Dishwasher heating element
Scale coating reduces efficiency, spots on dishes
$150–$400 repair
~8 months without treatment
11
Water heater
Scale on tank/element, 25–40% efficiency loss
$300–$800 repair or early replacement
~11 months without treatment
14
Tankless water heater
Heat exchanger scale — potential failure
$500–$1,500 repair or replacement
~14 months without treatment
16
Washing machine
Scale on drum and heating element
$200–$600 repair
~16 months without treatment
Central Ohio Hardness Reference
Columbus (city)9–11
Powell / Lewis Center14–17
Pickerington14–18
Dublin12–15
Westerville11–13
New Albany13–16
Grove City10–13
Hilliard10–12
Get Your Exact Number — Free
Jerry tests your water on-site with professional equipment. You'll know your exact hardness, iron level, TDS, and pH — not an estimate.