Every year, your municipal water utility mails or publishes an annual Consumer Confidence Report. It lists detected contaminants, compares them to federal limits, and concludes — almost universally — that your water is safe. But the report is built on a framework that was last meaningfully updated decades ago, and it omits more than it reveals.
EWG's national Tap Water Database — the most comprehensive analysis of its kind — examined water quality data from nearly 50,000 U.S. water systems collected between 2021 and 2023. It identified 324 distinct contaminants in drinking water across the country.
The EPA's Safe Drinking Water Act currently regulates approximately 90 contaminants. In the past 30 years, the EPA has set exactly one new Maximum Contaminant Level for hazardous chemicals — the six PFAS compounds addressed in 2024.
The gap between 324 detected and 90 regulated is not a rounding error. It means that roughly 234 chemicals found in U.S. tap water have no legal limit, no required testing, and no mention in your annual water report — regardless of their concentration or health effects.
What Your CCR Actually Shows
Your Consumer Confidence Report (CCR) lists detected contaminants and compares them to EPA Maximum Contaminant Levels (MCLs). It does not show contaminants below detection limits, unregulated contaminants, or how detected levels compare to health-based guidelines that are stricter than federal law. A result listed as "ND" (not detected) means below the detection threshold of the test — not zero.
When your utility reports a contaminant, it typically shows the detected level versus the MCL. What it almost never shows is the MCLG — the Maximum Contaminant Level Goal — which is the level at which EPA's own science says there is no known adverse health effect. Understanding the difference between these three numbers is the key to reading your water report honestly.
MCLG
Health Goal
The level at which no known adverse health effect occurs. Set by EPA science. Not legally enforceable.
MCL
Legal Limit
The enforceable maximum. Set as close to the MCLG as "feasible" given cost and technology. This is what your CCR reports against.
EWG HEALTH GUIDELINE
Science-Based Target
Independent health-protective limits based on current science. Often far stricter than both MCLG and MCL.
For many of the most dangerous contaminants, the MCLG is zero — meaning EPA's own science acknowledges there is no safe level. Yet the legally enforceable MCL is set orders of magnitude higher, because the law requires the EPA to balance health protection against the cost of treatment. Your water report shows compliance with the MCL. It does not tell you whether you are anywhere near the health goal.
| CONTAMINANT | MCLG (HEALTH GOAL) | MCL (LEGAL LIMIT) | EWG HEALTH GUIDELINE | GAP |
|---|---|---|---|---|
| Arsenic | 0 (no safe level) | 10 ppb | 0.004 ppb | 2,500× |
| Chromium-6 | No federal limit | No federal limit | 0.02 ppb | No limit at all |
| Lead | 0 (no safe level) | 15 ppb action level | 1 ppb | 15× |
| PFOA / PFOS | 0 (no safe level) | 4 ppt (2024 rule) | 1 ppt | 4× |
| Nitrates | 10 mg/L | 10 mg/L | 0.14 mg/L (infants) | 70× for infants |
Sources: EPA National Primary Drinking Water Regulations; EWG Tap Water Database; EWG Health Guidelines (2024)
The EPA's standard exposure model for setting MCLs assumes a 70-kilogram adult drinking 2 liters of water per day over a 70-year lifetime. This is the baseline from which "safe" is calculated. It does not account for children, infants, pregnant women, immunocompromised individuals, or people who drink more than 2 liters per day.
It also does not account for cumulative exposure — the fact that you are not consuming one contaminant in isolation, but a mixture of dozens simultaneously. A landmark 2019 EWG study found that the combined cancer risk from the mixture of contaminants in U.S. tap water could contribute to more than 100,000 cancer cases nationwide — even when each individual contaminant was within its legal limit.
Your water report does not show mixture risk. It shows each contaminant in isolation, compared to a limit calculated for a single contaminant in a single adult. This is not fraud — it is the limitation of a regulatory framework that was designed in a different era of science.
Your Report Is a Snapshot. Your Water Is Not Static.
Your CCR reflects water quality during the testing period — typically the prior calendar year. It does not reflect what your water contains today, or what it will contain next year. Municipal chlorine dosing changes seasonally and with staffing. Arsenic levels fluctuate with groundwater recharge and drought. PFAS contamination is expanding, not contracting — 143 million Americans are now exposed, up from estimates of 45% of tap water just two years ago. The pipes delivering water to your home are aging, not improving.
This is why AION designs systems to handle what your water will contain, not just what it contains today. A system sized exactly for today's contamination profile will be inadequate the moment that profile changes — and it will change.
Find your CCR
Search your utility's name + 'Consumer Confidence Report' or 'water quality report'. Most utilities post it on their website. You can also use EWG's Tap Water Database at ewg.org/tapwater — enter your zip code to see what has been detected in your water system.
Look at the detected level, not just the compliance status
A result of 'IN COMPLIANCE' means the detected level is below the MCL. It does not mean the level is below the MCLG or EWG health guideline. Find the actual detected concentration and compare it to EWG's health guidelines at ewg.org/tapwater.
Note what is not listed
Unregulated contaminants — including most PFAS compounds, many pesticides, pharmaceutical residues, and microplastics — will not appear on your CCR at all. Their absence from the report does not mean their absence from your water.
Check the 'ND' entries carefully
'Not Detected' means below the detection limit of the test used — not zero. The detection limit for some contaminants is higher than the EWG health guideline, meaning a contaminant could be present at a health-relevant concentration and still be reported as 'ND'.
Look for the source water assessment
Your CCR should include a source water assessment identifying potential contamination sources near your water supply — agricultural runoff, industrial sites, military bases. This tells you which contaminants to be most concerned about in your specific area.
What AION Filters That Your Report Doesn't Cover
AION systems are designed around the full contamination landscape — not just the 90 regulated contaminants. The AION PFAS MOF/COF media achieves 99%+ removal across all six PFAS families including GenX, using Metal-Organic Framework technology with 6,000+ m²/g surface area — five times greater than standard activated carbon. The AION REDOX electrochemical stage destroys bacteria, viruses, lead, glyphosate, chromium-6, and microplastics through a galvanic reaction at +950 mV ORP — no power, no chemicals. The Catalytic Carbon CORE uses Centaur® media to destroy chloramines that standard carbon cannot break.
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