Where the data comes from
Four government sources, joined by government ID and placed by distance from your office. This page lists each one, how often it changes, what a row shows, and what it does not prove.
Sources
| Source | Refresh | What it shows | What it does not prove | Coverage |
|---|---|---|---|---|
| EPA UCMR 5 | Final release. File last modified Oct 15, 2026. | A lab result for PFOA or PFOS at a named sample point on a date. 10,313 systems in the file. | Not a violation (EPA's caveat below). Not today's water: EPA says the data "are not real-time" and many providers act after reporting. Not necessarily the system's own source (purchased water). Its ZIPs "are not the definitive service areas." | National. Systems over 3,300 people, plus 800 sampled small ones. |
| EPA ECHO (ICIS-NPDES) | Weekly extract. Last Oct 30, 2026. | A formal action on a wastewater permit: type, date, lead agency, penalty listed. | Not a current problem: an order often settles an older case. "Penalty listed" isn't "paid"; ECHO doesn't show amounts collected. | TX, OK, LA, NJ loaded. NM and AR failed our checks. |
| EPA SDWIS (Envirofacts) | Quarterly. Pulled Nov 6, 2026; newest Texas violation begins Jun 30, 2026. | Population, primary source, the administrator on file, health-based violations with compliance period and status. | That the administrator decides on engineering (it may be an operator or manager). That a violation is still open: we print "Open" or "returned to compliance" with its date. | TX, OK, LA, NM |
| TWDB SFY 2027 DWSRF IUP | Yearly plus amendments. Effective Oct 1, 2026. | Entity, PWS ID, rank of 431, requested phases, project cost, and whether it is on the Appendix K invited list. | Not funding, approval or an award. Applications are by invitation only. It doesn't show whether an engineer is already engaged. | Texas only |
| Census 2024 Gazetteer (ZCTA, county, place), 2020 ZCTA–county file, 2024 county adjacency | Static | Distance from your ZIP. | Exact plant or service-area location. County placements say "about N miles." | National |
We fix known errors in the source files, such as a ZIP listed in the wrong county, and we flag every fix on the row.
What a PFAS row means, and what it doesn't
"UCMR 5 results do not indicate compliance or noncompliance with the PFAS NPDWR Maximum Contaminant Levels."EPA, ECHO PFAS tools, checked Nov 7, 2026
- EPA's PFOA and PFOS limit is 4.0 ppt, judged as a running annual average at each sampling point, with compliance due in 2029. On May 18, 2026 EPA proposed letting systems request until 2031 (EPA PFAS rule page).
- A UCMR 5 row is one lab result at a named sample point on a date. We print the highest single result, the sample point, the next result at that point, and how many of the system's PFOA/PFOS results were above 4.0 ppt.
- "Above" is strict. Nationally 1,739 systems are at or above 4.0 ppt, but only 1,711 are above it.
- The sample point may take purchased water. 64 of the 101 Texas systems above 4.0 ppt list purchased water as their primary source.
How rows are joined
- Water records join on the PWS ID: UCMR 5 to SDWIS (the administrator on file) to the TWDB list's printed PWS ID.
- A TWDB row gets a contact only when the printed PWS ID's SDWIS name matches the applicant. Of the printed PWS IDs, 390 are verified and 36 are held for review with no contact attached.
- Wastewater plants are ECHO NPDES permits and stay separate rows. When the town's water system matches the permittee by name and county, its administrator is shown and labelled as the town's water contact, not the permit contact.
- School package plants and non-utility permits are removed.
- Distances come from Census 2024 ZCTA centroids. A system placed by county says "about N miles", and only counts when the whole county fits inside your radius.
How we check
- Every row is re-checked against the raw source file before it shows. A mismatch removes the row.
- On Nov 6, 2026 an independent check, written separately from the engine, re-derived 30 random records by hand from the official sources on territories the engine's builders never used. 30 matched: 621 of 621 fields.
- 331 of 331 record-to-utility joins were right, and 788 of 788 cited source links opened (two EPA links answered on a retry).
- Every wrong record a customer reports becomes a permanent test case.
How often there is something new
ECHO's extract is weekly; we check it weekly. In the 4 complete weeks Sep 14, 2026 to Oct 11, 2026, ECHO listed 10 orders within 100 miles of Dallas and 12 near Houston, and fewer near Austin (3), Tyler (5) and San Antonio (3). UCMR 5 is final and won't change; SDWIS refreshes quarterly; the TWDB plan changes when it is amended.