A Consumer Confidence Report (CCR) is the yearly water quality report that a US community water system must deliver to its customers by July 1. Read it in three steps: find where your water comes from, find the table of detected contaminants, and check whether any violation is marked. Hardness is usually not part of the required content, so you may need to look for it in a separate utility page, or use our lookup page.
Who gets a CCR and when
Each existing community water system must deliver its report by July 1 each year (40 CFR 141.152). The report must contain data from the previous calendar year, or from the most recent calendar year before that. A new system delivers its first report by July 1 of the year after its first full calendar year of operation.
If you rent, the report may go to the building owner or may be posted online. Check the utility’s website or call the phone number printed on your water bill. This guide covers the United States. Other countries have different rules, and their utilities publish hardness in other ways.
What the report must contain
The federal rule (40 CFR 141.153) lists the minimum content. The parts you will meet most often are these.
- Water sources. Each source, its type (surface water or groundwater) and the commonly used name and location of the water body.
- Definitions. The report defines the maximum contaminant level goal (MCLG) and the maximum contaminant level (MCL). Other terms such as action level or treatment technique appear when they apply.
- Detected contaminants. For each regulated contaminant that was detected, the table gives the MCL and MCLG in the same units, the highest level found, the range of detections, and the likely source.
- Violations. Any MCL, monitoring or treatment violation must be clearly marked and explained, with its duration, health effects and the steps taken to fix it.
- Other items. Results for unregulated contaminants where monitoring was required, a summary if Cryptosporidium or radon were found, general information about contaminants in drinking water, a phone number for questions and details of public participation opportunities.
- Language access. Communities with many consumers who have limited English must provide translated information or help.
How to read the detected contaminants table
The table is the core of the report. Read one row at a time from left to right.
| Column | What it tells you |
|---|---|
| Contaminant | The substance that was detected |
| MCLG | The goal. A level below which no known health risk exists |
| MCL | The legal limit the utility must meet |
| Highest level or average | The worst result in the reporting year |
| Range | Lowest to highest result across samples or sites |
| Violation (yes or no) | Whether the limit was exceeded |
| Likely source | Where the substance usually comes from |
Three checks are worth making.
- Compare the highest level with the MCL. A result below the MCL is compliant. A result close to the MCL is worth noting but is not itself a violation.
- Check the units. Values are often in mg/L (the same as parts per million) or in µg/L (parts per billion). The unit changes the number by a factor of 1,000, so read the unit before comparing.
- Look at the range as well as the average. A wide range can mean different wells, different treatment plants or different seasons.
If the report marks a violation, it should say what the health effect is and what the utility did. If something is unclear, ask the utility. This guide is general information, not medical advice.
Where hardness fits
The federal content list above does not include hardness. Hardness is not a contaminant with a health-based limit. EPA’s secondary drinking water guidance covers 15 contaminants, mostly for taste, colour and odour, and calls those levels non-enforceable. Hardness is not listed there as its own entry. It appears only as an effect connected with total dissolved solids, whose guideline is 500 mg/L.
Utilities often add hardness voluntarily. If your CCR has a “other information” or “water characteristics” section, look for these labels:
- Hardness, total hardness, or hardness as CaCO₃
- Calcium and magnesium
- Alkalinity (a different measure, do not confuse it with hardness)
- Grains per gallon (gpg), where 1 gpg is 17.1 mg/L
The USGS classes are soft (0 to 60 mg/L), moderately hard (61 to 120), hard (121 to 180) and very hard (over 180). The USGS describes hardness as not a health concern, but a nuisance. It reacts with soap and forms scale when heated, for example in a water heater.
Examples from our data
A single city can have more than one number, because supply zones differ. These are the medians in our data, with the range across zones where one is published. Each city page shows its source and date.
| City | Median (mg/L CaCO₃) | Median (gpg) | Range across zones (mg/L) |
|---|---|---|---|
| Boston | 13.1 | 0.8 | 11.0 to 15.6 |
| Seattle | 26.4 | 1.5 | not published |
| Charlotte | 32.0 | 1.9 | 27.0 to 35.0 |
| Denver | 105.0 | 6.1 | 55.0 to 124.0 |
| Houston | 110.0 | 6.4 | 43.4 to 137.0 |
| Los Angeles | 128.0 | 7.5 | 78.0 to 280.0 |
| Phoenix | 237.0 | 13.9 | 172.0 to 302.0 |
| Las Vegas | 280.0 | 16.4 | not published |
| San Antonio | 299.6 | 17.5 | 256.8 to 342.4 |
| Indianapolis | 317.0 | 18.5 | 148.0 to 460.0 |
The Phoenix and San Antonio figures are computed from published data, not measured directly. The method is shown on each page. Where a range is shown, the figure at your address may be well away from the median. A utility map or a table by zone is more useful than a citywide number.
From the report to a decision
Once you have a hardness figure, the calculator converts it between mg/L, gpg, °dH and °fH and estimates the scale effect for your household. Use your CCR for safety questions, and use your hardness figure for appliance and softener questions. They answer different problems.
FAQ
Is hardness a violation if it is high? No. There is no federal limit for hardness in drinking water. A very hard supply is a nuisance because of scale and soap use, and the CCR will not flag it as a violation.
My CCR does not mention hardness. How do I find it? Check the utility’s water quality pages, call the number on your bill, or enter your ZIP code on our lookup page. Ask for the figure for your service zone, and ask which unit it is in.
Does a clean CCR mean my tap water is fine? The CCR reports on the utility’s supply, up to the point where it enters the distribution system and at monitored sites. It does not describe the pipes inside your building. If you are concerned about lead or other in-home issues, ask your utility about testing. This is general information, not medical advice.
Sources
- eCFR, 40 CFR 141.152, Timing, form, and manner of delivery (Cornell LII copy): https://www.law.cornell.edu/cfr/text/40/141.152
- eCFR, 40 CFR 141.153, Content of the reports (Cornell LII copy): https://www.law.cornell.edu/cfr/text/40/141.153
- US EPA, Secondary Drinking Water Standards: Guidance for Nuisance Chemicals: https://www.epa.gov/sdwa/secondary-drinking-water-standards-guidance-nuisance-chemicals
- USGS, Water Science School, Hardness of water: https://www.usgs.gov/special-topics/water-science-school/science/hardness-water
- City figures: source pages linked from each city page above.