The problem
Hardness describes dissolved calcium and magnesium. It shows up as scale on fixtures, spots on glassware, and buildup in water heaters.
It is reported in grains per gallon (gpg) or milligrams per liter (mg/L as CaCO3). One gpg is about 17.1 mg/L.
What public data can and cannot say
Can tell you
- Your utility's Consumer Confidence Report often lists a hardness range for the system.
- The ZIP public-system report can show what the serving utility has reported.
Cannot tell you
- A system-wide range does not tell you the reading at your tap.
- Public data does not tell you how your plumbing or water heater is affected.
How to test
- Hardness test strips give a quick gpg range.
- A certified lab report gives a precise number if you are sizing a softener.
System types compared
| System type | Format | What to check on the listing | Read |
|---|---|---|---|
| Ion-exchange softener | Whole-house, salt-based | Grain capacity, regeneration settings, drain and salt needs, local discharge rules | Reviews |
| Salt-free conditioner | Whole-house, media-based | What the seller says it does and does not change; it is not the same as softening | Reviews |
| Under-sink RO | Point of use | Pre-treatment needs on very hard water; membrane replacement interval | Reviews |
Ion-exchange softener
Grain capacity, regeneration settings, drain and salt needs, local discharge rules
ReviewsSalt-free conditioner
What the seller says it does and does not change; it is not the same as softening
ReviewsUnder-sink RO
Pre-treatment needs on very hard water; membrane replacement interval
Reviews
Referred equipment
Whole-house
Aquasana Rhino EQ-1000
Best for: Long-term value, low-maintenance homes
ReferralEditor's referral. We may earn a commission; the seller fulfills the order. How we make money · Disclosure
Sources
FAQ
- Is hard water unsafe?
- Hardness is a mineral measurement. HU does not make health claims about it; read your utility report and talk to a qualified professional for health questions.
- Does a conditioner soften water?
- Salt-free conditioners do not remove hardness minerals the way ion exchange does. Check the seller's own description of what the product changes.