Methodology: Water utilities, population served & registered phone
Every figure carrying this label on a county page is computed exactly as described below, from public government data. Nothing is estimated or editorialized.
| What it measures | community water systems (PWS_TYPE_CODE = 'CWS') that are ACTIVE (PWS_ACTIVITY_CODE = 'A'), assigned to this county via COUNTY_SERVED (name-resolved to county FIPS), ordered largest by POPULATION_SERVED_COUNT first (NULLs last, then name), LIMIT 5. Population served is the EPA-registered estimate for the system, not a county population. PHONE: we publish the registered PHONE_NUMBER only, labelled 'EPA-registered contact ... (verified {quarter})' where {quarter} is the SDWIS snapshot vintage — it is not an emergency or after-hours line; the number on your water bill stays primary, and an empty phone renders nothing. PRIVACY: EMAIL_ADDR, ADMIN_NAME, and address fields exist in the source but are NEVER ingested or published, because small systems register a private individual's personal contact information. |
|---|---|
| Unit | — |
| Source dataset | EPA — Safe Drinking Water Information System (SDWIS) |
| Data version / accessed | through 2026-07 (cube build 2026-07-21b, generated 2026-07-21) |
| Exact source fields | PWSID, PWS_NAME, POPULATION_SERVED_COUNT, PWS_TYPE_CODE, PWS_ACTIVITY_CODE, COUNTY_SERVED, PHONE_NUMBER |
| Formula | top 5 dim_water_system rows by population_served |
| Predicates / filters | community water systems (PWS_TYPE_CODE = 'CWS') that are ACTIVE (PWS_ACTIVITY_CODE = 'A'), assigned to this county via COUNTY_SERVED (name-resolved to county FIPS), ordered largest by POPULATION_SERVED_COUNT first (NULLs last, then name), LIMIT 5. Population served is the EPA-registered estimate for the system, not a county population. PHONE: we publish the registered PHONE_NUMBER only, labelled 'EPA-registered contact ... (verified {quarter})' where {quarter} is the SDWIS snapshot vintage — it is not an emergency or after-hours line; the number on your water bill stays primary, and an empty phone renders nothing. PRIVACY: EMAIL_ADDR, ADMIN_NAME, and address fields exist in the source but are NEVER ingested or published, because small systems register a private individual's personal contact information. |
| Date semantics | EPA registry snapshot; refreshed quarterly |
| Window boundaries | not date-windowed — current EPA registry snapshot (refreshed quarterly) |
| Rounding | none |
| Suppression rule | module hidden when the county has no registered community system |
| Minimum sample (min_n) | 1 |
| Geography | US county (FIPS) |
Internal build query
This query runs against our internal data cube (private cube_*/fct_* tables built from the public sources below). It is exact but not runnable by a reader — use the public reproduction recipe that follows.
SELECT name, population_served
FROM cube_county_water
WHERE county_fips = :fips
ORDER BY population_served DESC NULLS LAST, name
LIMIT 5;Reproduce from the public source
This recomputes the figure from the raw public dataset. Public data is live and may run ahead of our snapshot (see the data version above); numbers can differ by rows added since our ingest vintage.
EPA SDWIS / Envirofacts WATER_SYSTEM — data.epa.gov/efservice:
WATER_SYSTEM/PWS_TYPE_CODE/CWS/PWS_ACTIVITY_CODE/A/STATE_CODE/TX/JSON
Join to WATER_SYSTEM county service area; keep this county; order by
POPULATION_SERVED_COUNT desc; take the top 5.Worked example: Harris County's largest registered community water system is CITY OF HOUSTON.
Change log
2026-07-21 (r3) — window boundaries corrected (no windowed metric reads "not windowed"); LIMIT/ordering/geography/status predicates documented; the query relabeled the internal build query and paired with a public raw-source reproduction recipe.
2026-07-21 — record published with source URL, exact fields, predicates, window boundaries, rounding, suppression, and a worked example. Prior records disclosed a formula only.
Corrections
Spotted an error? Corrections: [email protected]. We publish the fix and note it in this change log.
Independent professional (adjuster/restoration) review of the guidance built on these figures is pending and blocks release (D2). This record documents the data method only; it is not insurance, legal, or engineering advice.