How to Read Your Water Quality Report (and What to Filter Based on It)
Every US water utility is required by the EPA to publish an annual Consumer Confidence Report (CCR) — a plain-language summary of what is in your tap water, delivered by July 1st each year. Most people receive it and throw it away. This is a mistake.
Reading your CCR takes 10 minutes. It tells you whether you need a filter at all, and if you do, exactly which contaminants to address — which tells you exactly which NSF certification to require. Here is how to read it.
Step 1 — Find your CCR
If your utility mails it, check your last water bill insert. If not:
- US: EPA CCR lookup tool — enter your ZIP code or utility name
- UK: Contact your water company (Thames Water, Anglian Water, etc.) for the annual Water Quality Report, or check the Drinking Water Inspectorate (DWI) database
If you are on a private well, you do not receive a CCR — your water is not tested. Get a private lab test. Tap Score and National Testing Laboratories offer comprehensive well-water panels.
Step 2 — Understand the three columns that matter
Most CCRs show three numbers for each contaminant:
MCLG (Maximum Contaminant Level Goal): the health-ideal target set by the EPA, based purely on science. Often zero for carcinogens (PFAS, arsenic, lead). Not legally enforceable.
MCL (Maximum Contaminant Level): the legally enforceable limit. Usually higher than the MCLG because of technical and economic feasibility. If your CCR shows a result above the MCL, your utility is in violation and must notify you.
Your water’s level: the measured concentration. You want this to be below the MCL — and ideally as close to the MCLG as possible.
Step 3 — The contaminants to look at first
Not all contaminants are equal. Start with these, in priority order:
Lead
Lead has an MCL of 15 ppb under the EPA Lead and Copper Rule, but the MCLG is zero — there is no safe level. The CCR reports whether your utility has any sites above the action level (15 ppb). But here is what many reports do not tell you clearly: lead contamination usually comes from household plumbing (lead solder, older lead service lines), not from the treatment plant. If your home was built before 1986, test your tap directly, regardless of what the utility report shows.
If lead is detected or suspected: require NSF 53 or NSF 58 certified filter. Brita Elite, ZeroWater, Pur Plus, or any RO system covers this.
PFAS (Per- and polyfluoroalkyl substances)
As of April 2024, the EPA set MCLs for six PFAS compounds: 4.0 ppt (parts per trillion) for PFOA and PFOS individually; 10 ppt each for PFNA, PFHxS, and HFPO-DA. Utilities have until 2027 to finish initial monitoring and until 2029–2031 to achieve compliance.
If your CCR shows any PFAS above these levels, require NSF 58 certified reverse osmosis. This is the only filter type with current independent certification for PFAS reduction. Standard activated carbon pitchers (Brita Standard) are not certified.
Nitrates
MCL: 10 mg/L (10 ppm). Relevant primarily for well water in agricultural areas and for households with infants under 6 months (nitrates interfere with blood oxygen in newborns — the “blue baby syndrome” risk). If you have a private well near farmland, test annually.
If nitrates are elevated: require NSF 58 (RO) certified system — activated carbon does not remove nitrates.
Arsenic
MCL: 10 ppb. Naturally occurring in groundwater in some US regions (New England, Southwest, Midwest). More common in well water than municipal.
If arsenic is detected above 5 ppb: require NSF 58 (RO) or NSF 53 certified for arsenic specifically.
Step 4 — Region-specific patterns
Older urban homes (US Northeast, Midwest, UK pre-1970s): lead from service lines and solder is the primary risk. Test your tap water directly. Buy NSF 53 minimum.
Well water (rural US): iron, sulphur, bacteria, nitrates, and arsenic depending on geology. Get a full well-water panel (iron, hardness, bacteria, nitrates, arsenic, pH). Whole-house multi-stage is typically required.
US Southwest (Arizona, New Mexico, Nevada): high TDS, arsenic, fluoride from geological sources. NSF 58 RO system is the defensible choice.
UK (East Anglia, Home Counties): hard water (high calcium/magnesium) is the primary complaint. A water softener or descaler addresses scale better than a drinking water filter. If drinking water quality is the concern, a carbon filter addresses chlorine taste — UK tap water PFAS monitoring is less mature than the US EPA framework.
Step 5 — Match your CCR result to a filter type
| CCR result | Filter type required | Minimum NSF standard |
|---|---|---|
| Chlorine taste only | Activated carbon pitcher or faucet | NSF 42 |
| Lead detected or older home | Carbon block with lead reduction, or RO | NSF 53 or NSF 58 |
| PFAS above 4 ppt (PFOA/PFOS) | Reverse osmosis | NSF 58 |
| Fluoride concern | Reverse osmosis or activated alumina | NSF 58 |
| Arsenic above 5 ppb | Reverse osmosis | NSF 58 |
| Nitrates above 5 ppm | Reverse osmosis | NSF 58 |
| Well water (bacteria, iron, sediment) | Whole-house multi-stage + UV | NSF 53 + UV cert |
| General reassurance, soft water | Pitcher or faucet filter | NSF 42 |
The most common answer for city-water households in the US and UK is: chlorine and taste only — which means a $35–$45 pitcher with an NSF 42 or NSF 53 certified filter is the correct and sufficient answer. Not a $300 under-sink RO system.
If your CCR shows PFAS above the new EPA MCLs, the correct answer changes sharply — to NSF 58 certified RO.
Read the report. Then buy the filter.
Sources: EPA Safe Drinking Water Act regulations; EPA April 2024 PFAS National Primary Drinking Water Regulation; NSF/ANSI 42, 53, 58 standards. CCR requirement under EPA 40 CFR Part 141 Subpart O.