Data sources: EPA, SDWA Last updated: September 2026

ZipCheckup guide: A plain-English guide to understanding your annual Consumer Confidence Report — what the numbers mean, which contaminants matter, and when to worry.

What Is a CCR?

A Consumer Confidence Report (CCR) — also called a Water Quality Report or Annual Drinking Water Quality Report — is a document your water utility must publish every year. It summarizes where your water comes from, what was detected in testing, and whether any EPA standards were exceeded.

The CCR is required under the Safe Drinking Water Act (SDWA) for all community water systems serving 15 or more connections. This covers about 148,000 public water systems serving approximately 300 million Americans (EPA SDWIS data).

The problem: most people glance at the CCR and toss it. The data is genuinely useful — but only if you know what the abbreviations mean and which numbers actually matter.

Finding Your Report

Your utility publishes the CCR online and may also mail a paper copy. To find it:

1. Search "[your utility name] water quality report" — most publish PDF versions on their website
2. Check the EPA's CCR search — epa.gov/ccr links to reports by state
3. Call your water utility — the number is on your water bill
4. Check your ZIP code — look up your ZIP on ZipCheckup to see violations and lead data pulled directly from EPA databases

If you are on a private well, you will not receive a CCR — your water is not tested or reported by any agency. See our well water safety guide for testing recommendations.

Key Terms Explained

The CCR is full of abbreviations. Here are the ones that matter:

Regulatory Standards

Term	Full Name	What It Means
MCL	Maximum Contaminant Level	The highest legally allowed level of a contaminant in drinking water. Enforceable
MCLG	Maximum Contaminant Level Goal	The level at which no known health risk exists. Not enforceable — it's a target. Often lower than the MCL
AL	Action Level	Used for lead and copper. If more than 10% of sampled taps exceed the AL, the system must take corrective action
TT	Treatment Technique	Instead of a numerical limit, the utility must use a specific treatment method (e.g., surface water filtration)
MRDL	Maximum Residual Disinfectant Level	Maximum allowed level of chlorine or other disinfectant

Measurement Units

Unit	What It Means	Context
ppm	Parts per million (= mg/L)	Used for most contaminants: nitrates, fluoride, TDS
ppb	Parts per billion (= µg/L)	Used for lead, arsenic, chromium-6. 1,000 ppb = 1 ppm
ppt	Parts per trillion (= ng/L)	Used for PFAS. 1,000 ppt = 1 ppb
pCi/L	Picocuries per liter	Used for radioactive contaminants: radium, uranium, radon
NTU	Nephelometric Turbidity Units	Measures water cloudiness. >1 NTU may indicate inadequate filtration

Statistical Terms

Term	What It Means
Range	The lowest and highest values detected across all sampling locations
Average	The arithmetic mean of all samples
90th percentile	Used for lead and copper. The value below which 90% of sample results fall. A result above the AL is an action level exceedance that triggers required actions; it is not a violation by itself
ND	Not Detected — the contaminant was below the lab's detection limit
N/A	Not Applicable — the system was not required to test for this contaminant

Reading the Data Table

Every CCR contains a table that looks something like this:

Contaminant	Unit	MCL	MCLG	Your System	Violation?	Source
Lead	ppb	AL = 15	0	90th%: 8	No	Corrosion of household plumbing
Nitrate	ppm	10	10	3.2	No	Runoff from fertilizer use
Total Trihalomethanes	ppb	80	—	45 (range: 12–78)	No	Byproduct of drinking water disinfection
PFOA	ppt	4	0	2.1	No	Industrial discharge

How to interpret each row:

1. Compare "Your System" to the MCL — if the detected level is below the MCL, the system is in compliance
2. Compare to the MCLG — this is the actual safety target. If the MCL is 15 ppb but the MCLG is 0, that means ANY detection carries some risk
3. Look at the range — a system-wide average of 5 ppb lead means some locations are higher. The range tells you the spread
4. Check "Violation?" — EPA groups violations separately. Health-based violations are MCL, MRDL, or treatment-technique violations. Monitoring and reporting violations mean required monitoring was not conducted or results were not submitted on time; they do not report a measured concentration. See the EPA ECHO definitions
5. Read "Source" — this tells you where the contaminant comes from. "Corrosion of household plumbing" means it's a local pipe issue, not the source water

What to Look For

Priority 1: Lead

• The MCLG for lead is zero. No amount is safe
• The 90th percentile value is what matters — above the applicable action level is an action level exceedance that triggers required steps. EPA explains that the exceedance itself is not a violation
• Even if below 15 ppb, any detection means some homes have elevated lead
• Your tap may not be one of the sampled taps — the system tests a subset of homes. Your home's result may be higher or lower
• See the lead guide and lead risk tool for more context. To learn your home's result, use Best Water Testing Kits

Priority 2: PFAS

• The 2024 rule set PFOA and PFOS MCLs at 4 ppt. On May 18, 2026, EPA proposed keeping those MCLs while allowing eligible systems to request up to two additional years, through 2031, to comply
• In a separate May 18, 2026 proposal, EPA proposed rescinding the PFHxS, PFNA, HFPO-DA, and Hazard Index regulations. Both actions remain proposals, so the 2024 final rule remains the current rule unless and until EPA finalizes changes. See EPA's current PFAS rule status
• Many CCRs don't yet include PFAS data — systems are still implementing monitoring
• If your CCR doesn't list PFAS, it doesn't mean they're absent — it may mean the system hasn't tested yet
• PFAS guide

Priority 3: Disinfection Byproducts (DBPs)

• Total Trihalomethanes (TTHMs): MCL 80 ppb. Formed when chlorine reacts with organic matter
• Haloacetic Acids (HAA5): MCL 60 ppb
• DBPs are carcinogenic at elevated levels. If levels are close to the MCL (within 75%), the system is under pressure
• Seasonal variation matters — DBP levels peak in summer when water temperatures are higher

Priority 4: Nitrates

• MCL is 10 mg/L — this standard was set specifically to protect infants from blue baby syndrome (methemoglobinemia)
• Levels above 5 mg/L indicate agricultural or septic influence and may trend upward over time
• If you have an infant, any detectable nitrates above 3–5 mg/L warrant caution

Priority 5: Radioactive Contaminants

• Radium-226/228: MCL 5 pCi/L combined
• Uranium: MCL 30 µg/L
• Gross alpha: MCL 15 pCi/L
• These are naturally occurring in certain geological formations. If detected, they tend to be persistent — they won't go away without treatment

What the CCR Doesn't Tell You

The CCR has significant blind spots:

1. Your exact tap result — Lead can enter water through service lines and household plumbing after treatment. The Lead and Copper Rule therefore requires sampling at customer taps, and the CCR reports the system's 90th-percentile result and sites above the action level. It does not report your home's result unless your tap was sampled

2. Private well water — If you're on a well, no government agency tests your water. You must test it yourself. Well water guide

3. All contaminants — EPA regulates about 90 contaminants. There are thousands of unregulated chemicals (pharmaceuticals, microplastics, many pesticides) that the CCR doesn't address

4. Real-time conditions — The CCR reports data from the PREVIOUS calendar year. Water conditions can change due to construction, pipe breaks, source water changes, or treatment failures

5. Distribution system decay — Water quality at the treatment plant may differ from water quality at your tap. Aging distribution mains can introduce lead, manganese, and disinfection byproducts

6. Contaminant interactions — The CCR reports each contaminant independently. It doesn't assess the cumulative health effect of multiple contaminants at low levels — a topic of ongoing research

What to Do Next

After reading your CCR:

1. Check your ZIP code report — ZipCheckup aggregates violation data, lead levels, radon risk, and flood data into a single view with historical context

2. If lead is detected (any level) — test YOUR tap. A first-draw sample from a state-certified lab costs $25–$50 and tells you what the CCR can't: your specific home's lead level

3. If PFAS isn't listed — contact your utility and ask whether they've completed initial PFAS monitoring under the 2024 rule. If not, consider getting an independent test ($200–$350)

4. If any contaminant is close to the MCL — it may occasionally exceed the MCL between reporting periods. Consider a point-of-use filter certified for that contaminant. Our filter guide matches contaminants to filter technologies

5. If violations are listed — check whether the violation is health-based or monitoring/reporting. Health-based violations (MCL exceeded) are more serious than monitoring violations (missed a test deadline), but both indicate management issues

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