How to read your water quality report (Consumer Confidence Report)

How to read your water quality report

Every US community water system serving 25+ people is required by the Safe Drinking Water Act to publish an annual Consumer Confidence Report (CCR) — sometimes called a "water quality report" or "annual drinking water report." It lists what's in your tap water, how the levels compare to EPA limits, and any compliance violations during the year.

This page walks through what the CCR sections mean, what to look for, and how the answer translates into a filter choice. We use Los Angeles Department of Water and Power (LADWP) data as a running example because LA has a publicly documented mix of contaminants typical of large urban surface-water systems.

What a CCR is

By July 1 each year, your local water utility must deliver (by mail, email, or web link in your bill) a report covering the previous calendar year's water quality. The format is standardized by EPA but utilities vary in how readable they make it.

If you haven't seen yours, check:

1. Your water bill — the link or insert is usually there.
2. Your utility's website — search "[your city] water quality report" or "[your utility name] CCR."
3. EWG's Tap Water Database — search by ZIP code; EWG sources its data from the same CCRs the utility files with the state.

The sections that actually matter

CCRs are long and structured. The sections you should focus on:

Source water

Where does your tap water come from? Three common patterns:

• Groundwater only — well sources, generally lower in disinfection byproducts but can carry naturally occurring arsenic, radium, hardness, or local industrial contamination.
• Surface water only — rivers, lakes, reservoirs. Generally higher in disinfection byproducts (the utility has to chlorinate to control microbiological risk) and seasonal turbidity. May include trace pharmaceuticals, pesticides, and runoff contaminants.
• Blend — most large urban utilities. LADWP, for example, blends Eastern Sierra surface water, Colorado River and State Water Project imports, and local groundwater. The blend ratio shifts seasonally with availability.

The source water section sets your baseline expectations for what contaminants are most likely to appear in the detection table.

Detected contaminants table

This is the heart of the CCR. A typical row looks like:

Key terms:

• MCL (Maximum Contaminant Level) — the EPA enforceable legal limit. Your utility is in compliance if detections are below MCL.
• MRDL (Maximum Residual Disinfectant Level) — same concept, but for disinfectants like chlorine.
• MCLG / MRDLG (Goal) — the EPA health-based goal. For some contaminants (like lead) the goal is 0 because there is no known safe exposure level; the MCL is a feasibility compromise. Detection below MCL does not mean detection at the goal.
• Detected level — the actual measured concentration, usually averaged or expressed as a 90th percentile across sampling sites.
• ppb / ppm — parts per billion or parts per million; 1 ppm = 1000 ppb.

What you're looking for: contaminants where the detected level is above 0 but below MCL, especially when the goal is 0. Lead is the most common example. Compliance doesn't mean absent.

Compliance violations section

Listed separately if any occurred. If your utility had violations during the reporting year, the section describes the contaminant, the time period, and corrective action. A history of violations is a stronger reason to filter than a single-year detection.

Treatment process

Most CCRs include a brief description of how the utility treats raw water — typically coagulation, sedimentation, filtration, and disinfection (chloramine or free chlorine). The treatment section is informational; it tells you what the utility removes before water leaves their plant, but not what your home plumbing or service line might add (lead from old pipes is the classic example — the utility's treatment can't address contamination introduced between the plant and your tap).

What to do with what you found

Translating CCR findings into a filter choice:

Lead detected (above zero, regardless of MCL compliance)

The EPA goal for lead is zero. If your CCR shows any lead detection, especially if your home was built before 1986 (when lead solder was banned) or 1930 (when lead service lines were widely installed), point-of-use filtration is worth doing for drinking and cooking water.

• Lowest cost: an NSF/ANSI 53 certified pitcher. Brita Elite and PUR Plus pitchers are the most common; both carry NSF/ANSI 53 for lead reduction on their respective Elite/Plus lines.
• Most thorough at moderate cost: an under-sink RO system carrying NSF/ANSI 58 (which covers lead reduction as part of broader contaminant reduction) and ideally a pre-filter stage with NSF/ANSI 53. See /best/best-under-sink-water-filters.
• Whole-home protection: a whole-house carbon filter with NSF/ANSI 53 certification, or a whole-house + under-sink RO combo. Cost-justified mainly if you're concerned about lead in shower or cooking water as well as drinking. See /compare/whole-house-vs-under-sink.

PFAS detected (any concentration)

EPA finalized national PFAS drinking water standards in 2024. If your CCR shows PFOA, PFOS, or other PFAS compounds at any level, filtration is the practical response while utilities upgrade treatment.

• At-tap reduction: an under-sink RO system. NSF/ANSI 58 covers a portion of PFAS reduction; NSF/ANSI 53 was updated in recent years to include certain PFAS protocols — verify per-product in WQA Gold Seal.
• We do not currently publish a "best filters for PFAS" page because the framing requires careful health-context language and per-PFAS-compound cert verification that we want to do thoroughly. Use /water-filter-finder with "PFAS" as your concern; it routes you to the right system type and cert standards.

Disinfection byproducts (TTHM, HAA5) above goal but below MCL

Common in surface-water systems. The simplest fix is a carbon-based filter — chlorine and chloramine react with organic matter in source water to form trihalomethanes, and activated carbon is effective at reducing both the disinfection byproducts and their chlorinated precursors.

• Pitcher or faucet-mount with NSF/ANSI 42 certification handles chlorine taste and odor; some models also carry NSF/ANSI 53 reduction for TTHMs.
• Whole-house carbon addresses chlorine in shower water (where chloroform exposure happens via inhalation rather than ingestion) as well as kitchen.

Hardness (typically reported as grains per gallon or mg/L as CaCO₃)

Hardness above ~7 grains per gallon (120 mg/L CaCO₃) starts affecting appliance lifespan, soap effectiveness, and skin/hair. Filtration alone doesn't soften water; you need either an ion-exchange softener or a salt-free conditioner. Both are whole-house point-of-entry installs.

Arsenic, fluoride, hexavalent chromium, radium

These are RO-territory contaminants. Under-sink RO carrying NSF/ANSI 58 with the specific reduction claim you need is the standard answer. APEC's WQA Gold Seal listing documents NSF/ANSI 58 reductions for all of arsenic V, fluoride, hexavalent chromium, and radium 226/228.

What we won't tell you

A few things you'll see other water-filter sites do that we deliberately don't:

• We won't tell you your water is "unsafe" or "toxic" based on a CCR reading. Some contaminants are concerning at any detection level (lead, PFAS); many others have clear EPA safety margins between detection and harm. The CCR shows you what's measurable; the safety determination involves dose, body weight, exposure duration, and individual sensitivity that we can't assess remotely. Talk to your utility, your state department of health, or your doctor for medical guidance.
• We won't generate scary contamination charts to push you toward our most expensive recommendations. Many readers genuinely need a $40 pitcher, not a $1,500 whole-house system, and pretending otherwise undermines the whole site's credibility.
• We won't claim that filtering all your water is always worth the cost. For some households (renters, low-detect CCRs, small budgets) the right answer is a pitcher and an honest CCR review every year.

Walk through an example: LADWP

Los Angeles is a useful example because the system serves ~4 million people, blends three source water types, and has its full CCR data on EWG's Tap Water Database.

Contaminants of note in LADWP's recent reporting (verify current year at the EWG link):

• Hexavalent chromium detected above EWG's health guideline. LADWP is in compliance with the EPA's total chromium MCL; California has its own hexavalent chromium MCL that some California utilities are still working toward. NSF/ANSI 58 RO is the standard mitigation.
• Total trihalomethanes and haloacetic acids above EWG's health guidelines but below EPA MCL. NSF/ANSI 42 or 53 carbon filtration mitigates.
• Hardness is moderate to high across most LADWP service areas. Softener or salt-free conditioner relevant for appliance protection.

A reasonable LADWP household setup, given those CCR signals: under-sink RO for drinking (handles hexavalent chromium + acts as broad-spectrum reduction); a whole-house carbon stage if shower-water disinfection byproducts are a concern; softener or conditioner if your specific service area exceeds 7 grains hardness.

See /city/los-angeles-water-quality-report for a more detailed breakdown of LADWP's specific data and filter implications.

Next steps

• Look up your own utility's CCR via EWG's Tap Water Database or directly through your water bill.
• Translate the contaminants you find into a filter type via /water-filter-finder — it accepts your specific concerns and home situation and recommends a filter category + cert standards to look for.
• Cross-reference any cert claim a product makes against the actual database via /certifications/nsf-53-vs-58-vs-401.

The most useful thing you can do today is read your own CCR. Then come back with specific contaminants in mind.