Well and water-source coordination — placement order and distances.

Plan the well and the OSSF together, because both sides of the rulebook impose setbacks: Table X requires soil absorption systems, unlined ET beds, surface spray areas, and drip irrigation to be 100 feet from wells and underground cisterns and tanks to be 50 feet, while public water wells require 150 feet (50 feet for tanks) and public water supply lines 10 feet (30 TAC §285.91(10) Table X). TDLR's well-drilling guidance states the mirror-image requirement for the well itself — 50 feet from a septic tank and 100 feet from drain fields or spray areas, with minimum well-construction specifications met — and a well may be as close as 50 feet to a property line (5 feet only with an oversized, pressure-cemented annular space) (TDLR, Technical Guidance on Well Drilling). These distances apply to neighboring and shared wells too, since Table X is keyed to the feature, not to ownership, and locations of water wells must be shown in subdivision planning materials and identified during the site evaluation (30 TAC §285.4(c)(1)(E); 30 TAC §285.30(b)); some counties add documentation for properties near wells (Texas Septic Guide — industry source).

Reviewed August 2026. Links go to the sources this answer was checked against.