Guide
How to read your water quality report
Your utility's annual Consumer Confidence Report, decoded: MCL vs. MCLG, ppm vs. ppb vs. ppt, the lead 90th percentile, hardness, and PFAS, with PA, NJ & DE examples.
Every community water system has to send customers an annual water quality report, called a Consumer Confidence Report (CCR)[1]. It lists what the utility detected and how that compares with the limits. Here's how to read one.
The key terms
| Term | Meaning |
|---|---|
| MCL | Maximum Contaminant Level: the legal limit[2] |
| MCLG | Maximum Contaminant Level Goal: the level with no known health risk. Not enforceable; for lead it's zero[3] |
| Action level | A trigger for extra steps. For lead it's 15 ppb at the 90th percentile[3] |
| MRDL | Maximum residual disinfectant level, the limit for chlorine and chloramine |
| ppm / ppb / ppt | Parts per million (mg/L), billion (µg/L), and trillion (ng/L). PFAS limits are in ppt. |
What to look for
- Any violation. A detection isn't a violation; a result above the MCL, or a missed test, is.
- The lead 90th percentile. It tells you about the utility's sampling, not your tap. Older homes may still have lead service lines; see lead.
- Disinfectant. Chlorine or chloramine? Philadelphia Water and New Jersey American Water's Raritan system use chloramine[4][5]. It matters for filter choice; see chloramine.
- Hardness. Often in the "secondary" or "other" table, in mg/L or grains per gallon (1 gpg = 17.1 mg/L)[6]. Philadelphia reported averages of 98, 152, and 168 mg/L at its three plants for 2024[7].
- PFAS. Compare PFOA and PFOS with the 4.0 ppt federal limit that takes effect in 2029[8], and with your state's limit: Pennsylvania 14 and 18 ppt[9], and Delaware 4.0 ppt since January 2026[10].
Skip the PDF
Our free water report pulls your utility's EPA records (violations, lead sampling, and PFAS results) by ZIP code and explains them in plain English. For hardness, use your utility's CCR or an in-home test.
More guides
Common questions
Where do I find my utility's CCR?
Most utilities post it on their website, and it's often mailed or linked from your water bill. You can also ask the utility directly.
My CCR shows no violations. Do I still need a filter?
Not necessarily. Some people still choose treatment for hardness, taste, chloramine, or PFAS levels below today's limits, and the CCR doesn't reflect your home's own plumbing.
Clean water starts with knowing what's in it.
Sources
- U.S. EPA: Consumer Confidence Reports (CCR) information for consumers. www.epa.gov/ccr/ccr-information-consumers
- U.S. EPA: National Primary Drinking Water Regulations. www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
- U.S. EPA: Basic information about lead in drinking water. www.epa.gov/ground-water-and-drinking-water/basic-information-about-lead-drinking-water
- Philadelphia Water Department: 2025 Drinking Water Quality Report. water.phila.gov/drops/2025-drinking-water-quality-report/
- NJ American Water: Raritan/Hunterdon/Mercer/Somerset typical water quality (PDF). amwater.com/njaw/resources/raritanhunterdonmercersomerset_twq.pdf
- USGS Water Science School: Hardness of water. www.usgs.gov/special-topics/water-science-school/science/hardness-water
- Philadelphia Water Department: 2024 Water Quality Report (PDF). water.phila.gov/wp-content/uploads/files/2024-pwd-water-quality-report.pdf
- U.S. EPA: Proposed PFOA and PFOS compliance extension rule. www.epa.gov/sdwa/proposed-pfoa-and-pfos-compliance-extension-rule
- PA DEP: PFAS MCL rule. www.pa.gov/agencies/dep/programs-and-services/water/bureau-of-safe-drinking-water/drinking-water-management/drinking-water-regulations/pfas-mcl-rule
- Delaware Public Health: PFAS in Delaware public drinking water. publichealthalerts.delaware.gov/pfas-in-delaware-public-drinking-water/
EPA records retrieved Oct 2026 from the EPA SDWIS and UCMR 5 public datasets. Utility records describe a water system, not the tap in your home. Records can lag and may be incomplete.