ZIP 77470
Water quality in Rock Island, TX (77470)
Drinking water in ZIP 77470 (Rock Island, Colorado County) comes from 13 public water system s on EPA's records. The list below is ranked by population served: the largest regional authority for your area appears first, smaller subdivisions and private systems below.
Combined population served: 13,361 people.
Public water systems serving ZIP 77470
Ranked by population served. Tier badges show how EPA records each utility's service area: "Serves your city" means EPA's geographic-areas table specifically lists Rock Island; "Serves your county" means the utility serves Colorado County (regional authorities are usually filed this way); "Billing address at this ZIP" means the utility files paperwork from this ZIP but EPA does not confirm it serves you.
- Serves your county
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More for TX
How we matched ZIP 77470: we translate the ZIP to a city and county via the Geonames postal database, then match against service-area cities and counties EPA has on file for each public water system. EPA does not publish authoritative service-area boundary maps for most systems, so there is still some guesswork; large regional authorities (e.g., county-wide water and sewer authorities) are usually filed at the county level even when they serve specific cities. Your water bill names the authoritative utility. Methodology.