Methodology
How we scored the Best Water Quality Reports in America 2026. Everything here is public so anyone can re-derive a score from the same sources.
Version 2026.1 · Published June 13, 2026 · Updated September 13, 2026 · By TapWaterData Editorial
What we measure, and what we don't
This is a ranking of the report, the document a resident receives, scored on how well it communicates water quality. It is not a ranking of the water itself, and a high score is not a safety claim. We judge utilities on communication because that is the gap the EPA's 2027 Consumer Confidence Report rule is built to close: clearer, more accessible, electronically delivered reports.
We read one published edition of each utility's report page by page and scored it on five pillars, weighted as below. Scores are absolute against the rubric, not graded on a curve.
The five pillars
Plain-language clarity
25% of scoreCan a non-expert actually read it?
Contaminant transparency
25% of scoreDo they show the numbers — including the bad news?
Information design
20% of scoreIs the data visual, or a wall of tables?
Digital accessibility & delivery
20% of scoreWeb-native, mobile, and lookup — or a buried PDF?
Timeliness & completeness
10% of scoreRecent data, full panel.
From sub-scores to a grade
Each pillar is scored 1–5. The weighted sum becomes a 0–100 report-clarity score, then a letter grade on fixed thresholds. Honorees (grade C and above) appear on the leaderboard with a tier. We publish honorees only — we do not print a public grade next to a utility that did not place, because the goal is to raise the floor, not to shame.
- A90–100
- B80–89
- C70–79
- D60–69
- Fbelow 60
- Platinum90+
- Gold80–89
- Silver70–79
Which utilities we reviewed
The 2026 cohort is 25 utilities, weighted toward larger systems and reports with a reputation for design, plus a set of smaller utilities chosen to test the range. We judged one published edition of each report, named and linked on each honoree's scorecard and in the also-reviewed list. This is a first edition; the cohort will expand.
- Philadelphia Water DepartmentPA
- Tucson WaterAZ
- DC WaterDC
- Denver WaterCO
- Mount Pleasant WaterworksSC
- Greenville WaterSC
- City of Grants PassOR
- San Francisco Public Utilities CommissionCA
- WSSC WaterMD
- East Bay Municipal Utility DistrictCA
- Austin WaterTX
- Medford WaterOR
- New York City DEPNY
- Akron Water SupplyOH
- City of Burlingame WaterCA
- City of RichmondTX
- Seattle Public UtilitiesWA
- LADWPCA
- San Jose WaterCA
- Fayetteville PWCNC
- Louisville WaterKY
- San Diego Public UtilitiesCA
- City of RedmondOR
- Massachusetts Water Resources AuthorityMA
- Honolulu Board of Water SupplyHI
Data sources
- Each utility's own published water quality report (CCR), one edition per utility. Each honoree's scorecard, and the also-reviewed list, names and links the edition we read.
- EPA Safe Drinking Water Information System (SDWIS).
- The EPA 2027 CCR Rule revisions and peer-reviewed CCR-accessibility research, which anchor the rubric.
Independence, corrections, and AI
Independence
No utility paid for placement, and displaying a badge is free and does not affect rank. TapWaterData earns affiliate revenue from filter recommendations elsewhere on the site. That revenue is firewalled from this ranking, which judges utilities and recommends no products.
Corrections
Scores are drawn from public documents. If a utility believes a score rests on an error, it can email hello@tapwaterdata.com. We review the source, correct it, and date the change in the corrections log.
Use of AI
Reports were read and scored with editorial judgment. AI-assisted tools helped organize notes; every published score and claim was verified by a person against the source report.
Corrections log
- September 13, 2026 · All scorecards
Each scorecard now names and links the exact report edition we scored, and notes any newer edition the utility has published. Some report links had pointed to pages that have since moved on to a newer edition.
- September 13, 2026 · Denver Water
The scorecard said the report disclosed two monitoring violations and a treatment deficiency and committed to a 2035 lead line replacement target. The two monitoring violations, and a significant deficiency related to storage conditions, are disclosed in Denver Water's 2025 report; the 2026 report we scored discloses one missed monitoring requirement. Neither report commits to 2035: both say that when the Lead Reduction Program was launched, all lead service lines were slated to be removed by 2035. The scorecard also gave the data year as 2024; the 2026 report covers 2025. Scores are unchanged.
- September 13, 2026 · Philadelphia Water Department
The scorecard said the report charts its highest PFOA result against the EPA's 4 ppt limit; its PFAS chart plots running averages against the state limits, and the 7.3 ppt figure sits beside the EPA's 4 ppt limit — which the report says applies from 2029 — in the data table. It also said every term and unit is translated, each chapter opens with what the data means for you, contaminants are visually encoded in multi-year trends, the address lookup maps each home to one of three plants, and a glossary closes the report. The report defines its terms in a glossary that comes before the data tables and pictures ppm, ppb and ppt; four of its charts carry a 'What this means for you' note; lead is its only multi-year chart; and some areas receive water from a mix of plants. The half point it loses on timeliness is its lead and copper results, last tested in 2022. Scores are unchanged.
- September 13, 2026 · WSSC Water
The scorecard described a map of three water sources and voluntary monthly PFAS monitoring since 2020. The map shows two river sources and the area where they blend, and the report describes quarterly PFAS testing from 2020, monthly from September 2022.
- September 13, 2026 · Mount Pleasant Waterworks
The scorecard said the report used 2025 data; it covers 2024. It called the swimming-pool comparison a spread; it is one panel on the page explaining how to read the water quality tables. It said the report avoids a spotless compliance line; the report states that the water meets or surpasses all state and federal standards, and its candor is about the system's pre-1991 history. Its screenshot caption said the cutaway shows exactly which aquifers supply the water; the wells draw from the Charleston Aquifer, and the utility also buys surface water.
- September 13, 2026 · DC Water
The scorecard described annotated basement photos. The report's pipe-identification photos are annotated pictures of lead, galvanized iron, copper and brass pipes, and the report does not present them as basement photos. Its timeliness note claimed a complete regulated panel; the report's tables list the contaminants that were detected.
- September 13, 2026 · Tucson Water
The scorecard said the report has no address lookup; it sends readers to the city's Water Quality Dashboard to see results for their address. Its screenshot caption described tens of thousands of voluntary samples a year; the report gives its voluntary sample and test counts without a time period, and the caption now quotes them.
- September 13, 2026 · San Francisco Public Utilities Commission
The scorecard said the report defers its full PFAS results to the website, that every section opens with a sixth-grade-reading-level summary box, and that its lead service line program is 96% complete. The report states that all 29 PFAS compounds it tested were not detected; five of its seven numbered sections include a plain-language summary box, and it states no reading level; and the 96% figure is its replacement of galvanized service lines that may have lead whips — it removed all known lead service lines in the 1980s. Scores are unchanged.
- September 13, 2026 · Greenville Water
The scorecard said every contaminant card shows the value, the goal and the limit, that no other report dares to drop the regulatory table, and that the card format surfaces fewer contaminants than a full table would. Some cards carry no goal or limit; the comparison with other reports is withdrawn; and the report does not indicate that results were left out — it reports 11 contaminants and states that none of the 29 PFAS chemicals or lithium were detected. Its transparency score is reviewed in a separate entry.
- September 13, 2026 · City of Grants Pass
The scorecard said the report runs its photo-contest winners full-bleed, that no other report attempts this, that its cover shows the Rogue River, and that its contaminant panel is complete. Only the first-place photo spans the cover (the second-place photo is on page 2), the comparison with other reports is withdrawn, the report does not name the river, and the timeliness note now lists what its tables cover.
- September 13, 2026 · East Bay Municipal Utility District
The scorecard said the report prints unregulated detections most utilities hide. Utilities must report these contaminants when they are detected, so it now says only that the report gives them a table of their own.
- September 13, 2026 · Medford Water, Honolulu Board of Water Supply, City of Redmond, San Diego Public Utilities, Austin Water, Massachusetts Water Resources Authority
Report titles now match the documents for Medford Water, the Honolulu Board of Water Supply, the City of Redmond and San Diego Public Utilities. Austin Water's link now points to an archive of the web report its review recorded, and the Massachusetts Water Resources Authority's to the report PDF its review recorded, rather than to a different format of each.
- September 13, 2026 · Tucson Water, DC Water, Denver Water, Mount Pleasant Waterworks, City of Grants Pass
Verdicts that named one factor as the only thing holding a report back now name it as the main one, matching sub-scores in which more than one pillar is below 5.
- September 13, 2026 · Mount Pleasant Waterworks, Tucson Water, DC Water, Denver Water
Mount Pleasant Waterworks' transparency score changed from 5 to 4, moving it from #2 to #5 (still Gold, now 80/100); Tucson Water, DC Water and Denver Water each move up one place. Its report prints its PFAS results, including PFOS at 6.6 ppt, in a table that gives no limits and says such compounds may not have health-based standards, without mentioning the EPA's 4 ppt limit that result is above. The top transparency score calls for results shown against the limits and problems disclosed plainly.
- September 13, 2026 · Greenville Water
Greenville Water's transparency score changed from 3 to 4 (74 to 79/100; still Silver, still #6). The lower score rested on the claim that its cards leave out contaminants a full table would show, which the report does not support. It shows lead and copper against the action level and reports its PFAS testing as a not-detected statement, the pattern of other reports scored 4.
- September 13, 2026 · Denver Water, San Francisco Public Utilities Commission, Tucson Water, Philadelphia Water Department, East Bay Municipal Utility District
Scores reviewed after these corrections and kept: Denver Water's transparency (5), because its 2026 report shows lead and PFAS results against the limits and explains its missed monitoring requirement plainly; San Francisco's transparency (4), matching other reports that give PFAS as a not-detected statement; Tucson Water's digital accessibility (2), the score every PDF-only report received; and Philadelphia's clarity (5). East Bay MUD's score is for the 2024-data report that was read, which its scorecard notes had already been replaced when the ranking was published.
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