To find hardness in your water quality report, look past the regulated contaminants to the table of “secondary”, “other” or “unregulated” parameters, and find the row called “Total hardness” or “Hardness (as CaCO3)”. Note the unit (ppm, mg/L or gpg) and whether the figure is an average or a range. If the report lists only calcium and magnesium, you can calculate hardness from them: 2.497 × calcium + 4.118 × magnesium.
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Every community water system in the US must send customers a Consumer Confidence Report (CCR) each year, by July 1. It’s free, it’s specific to your supplier, and it’s the figure most softener and dishwasher settings should start from. Here’s how to read it.
Step 1: get the right report
Search your water utility’s name with “water quality report” or “consumer confidence report”, or use the EPA’s CCR finder. Check two things before you read further:
- The supplier. The report must come from the utility that actually serves your address. In the Las Vegas area, for example, Henderson runs its own utility and publishes its own report, separate from the Las Vegas Valley Water District.
- The year. A report published in 2026 covers sampling from 2025. Older reports are fine for a rough idea, but sources and treatment change.
Step 2: find the hardness row
Hardness isn’t a health-based standard (the USGS and EPA note there’s no federal limit for it), so it’s never in the main table of regulated contaminants with MCLs and violations. Look for:
- A table titled “Secondary standards”, “Other parameters”, “Additional water quality data”, “Unregulated” or “Aesthetic”.
- Row names such as “Total hardness”, “Hardness (as CaCO3)” or “Hardness, total”.
- A separate FAQ or “about your water” box. Some utilities give the softener setting there in plain words.
If it isn’t in the report at all, the utility’s website often has a water quality data page or a hardness FAQ, or you can call and ask.
Step 3: check the unit
| Written as | Means | To get gpg |
|---|---|---|
| ppm, mg/L, mg/L as CaCO3 | Same number for water | Divide by 17.118 |
| gpg, grains/gal | Grains per US gallon | Already gpg |
| mmol/L | Millimoles per litre | Multiply by 5.847 |
| °dH, °f, °e | German, French, Clark degrees | Use the converter |
Watch for “as Ca”. Calcium reported on its own, in mg/L of calcium, is not total hardness. That’s the mistake behind many wrong softener settings.
Step 4: average, range or both?
Most reports show an average (or “typical”) value and a range from the lowest to the highest sample. Austin Water’s 2025 report is a good example: total hardness averaged 93 ppm (5.4 gpg) with samples from 70 to 126 ppm. Which number to use depends on the job:
| Task | Use | Austin example |
|---|---|---|
| Softener hardness setting | The upper part of the range, unless the utility recommends a figure | 126 ppm = about 7.4 gpg |
| Softener sizing and salt estimates | The average | 5.4 gpg |
| Dishwasher setting | The upper part of the range | 126 ppm = 1.26 mmol/L |
Some utilities make it simple. The Las Vegas Valley Water District’s 2026 report gives 280 ppm and tells customers to set their softener to 16. When the utility names a setting, use it.
Step 5: if only calcium and magnesium are listed
Some reports skip total hardness but list calcium and magnesium in mg/L. Convert each to its calcium carbonate equivalent and add them. The factors come from the molar masses: 100.09 ÷ 40.08 = 2.497 for calcium and 100.09 ÷ 24.31 = 4.118 for magnesium.
| Calcium | Magnesium | Total hardness | gpg |
|---|---|---|---|
| 40 mg/L | 10 mg/L | 141 mg/L | 8.2 |
| 60 mg/L | 20 mg/L | 232 mg/L | 13.6 |
| 80 mg/L | 25 mg/L | 303 mg/L | 17.7 |
Step 6: check for more than one source
Many systems blend sources, and the report says so near the front. The LVVWD gets about 90% of its water from Lake Mead and up to 10% from groundwater, mainly from April to October, and notes that some areas receive a blend. San Antonio’s water system draws on the Edwards and Trinity aquifers among other sources. If your report lists several sources with different hardness, your tap may vary through the year; a home test settles it. Our guide on how to test water hardness explains the options.
Three reports, three formats
| Utility | Where | What it gives |
|---|---|---|
| Las Vegas Valley Water District | 2026 Water Quality Report | 280 ppm and a softener setting of 16 gpg |
| Austin Water | 2025 report and its web page | 70–126 ppm range, 93 ppm average, gpg in brackets |
| San Antonio Water System | Water quality FAQ | A typical range of 15–20 gpg |
Full details for each city: Las Vegas, Austin and San Antonio, plus the comparison in water hardness by city.
Frequently asked questions
Why isn’t hardness in my water quality report?
Hardness has no federal health standard, so utilities don’t have to report it. Many do anyway. If yours doesn’t, check its website or call customer service.
Is “hardness as CaCO3” the same as calcium?
No. Hardness as CaCO3 counts calcium and magnesium together, expressed as calcium carbonate. A calcium-only figure is lower; use the formula above to get total hardness.
Which number should I put in my water softener?
The utility’s recommended setting if it gives one; otherwise the upper part of the hardness range, converted to gpg. Our hardness setting guide covers iron and blended water.
When are water quality reports published?
Community water systems in the US must deliver their CCR to customers every year by July 1.
Is my water hard if the report says 120 ppm?
It’s at the top of the USGS “moderately hard” band (61–120 mg/L); anything above 120 counts as hard. See the full water hardness scale.
