Texas · regulation guide
Austin Save Our Springs Ordinance
A citizen-adopted overlay inside the Barton Springs Zone that caps impervious cover and requires net-zero increase in pollutant loading — almost always tighter than the TCEQ Edwards rules it sits on top of.
- Statute
- Austin City Code §25-8 (Subchapter A, Article 13)
- Authority
- City of Austin Watershed Protection Department
Who this triggers for
- ›Any new development, redevelopment, or site plan application inside the Barton Springs Zone (the Recharge and Contributing Zones of the Barton Springs segment of the Edwards Aquifer, as mapped by the City).
- ›Projects in the broader Drinking Water Protection Zone (DWPZ) — the Barton Springs, Lake Austin, and Bull Creek watersheds — where IC caps run 15% net site area on unzoned land and up to 25–40% on zoned tracts depending on slope and gross/net site area.
- ›Subdivision plats, site plans, and building permits that would increase impervious cover, alter drainage patterns, or add a regulated pollutant load inside the SOS boundary.
- ›Amendments to previously approved SOS water-quality plans — new phases, added IC, or revised BMPs all require a fresh Watershed Protection review.
- ›Projects seeking a density or IC variance — these go to the full City Council under §25-8-514, not a staff administrative review.
The process
- 01
Boundary confirmation and tier determination
1–2 weeksConfirm whether the parcel is inside the Barton Springs Zone (BSZ) or the broader Drinking Water Protection Zone using City of Austin GIS. The SOS Ordinance only applies to the BSZ; DWPZ sites face related but less stringent §25-8 rules. Determine the applicable IC cap tier — 15% for unzoned BSZ land, 20–25% for most zoned BSZ tracts, with slope-based reductions under §25-8-422.
- 02
Site analysis and water-quality modeling
4–10 weeksA registered engineer delineates drainage areas, calculates pre-development pollutant loads for TSS, TP, TN, and fecal coliform, and models post-development loads. The net-zero rule in §25-8-514 requires that post-development annual loading not exceed pre-development loading for each regulated pollutant — typically achieved through biofiltration ponds, rainwater harvesting, and reduced IC footprints.
- 03
Watershed Protection review and site plan approval
90–180 daysThe SOS water-quality plan is submitted as part of the City site plan. Watershed Protection reviews BMP sizing, pollutant-removal credits, and long-term maintenance covenants. Expect at least one update cycle; Barton Springs sites commonly see two or three rounds of comments because of the sensitive-feature cataloguing and the interaction with the TCEQ WPAP running in parallel.
- 04
Council variance (only if above the cap)
6–12 months if pursuedIf the proposed IC or loading exceeds the SOS cap, the applicant must seek a variance from the full City Council under §25-8-514. Staff makes a recommendation, the Environmental Commission weighs in, and Council holds a public hearing. Variances are rare, contested, and often conditioned on additional BMPs, parkland dedication, or deed restrictions.
Costs and timelines
| Line item | Typical range |
|---|---|
| Site plan review fee (baseline, varies by project type) | $2,000 – $15,000+ |
| SOS water-quality plan engineering | $20,000 – $80,000 typical |
| Biofiltration / sedimentation pond construction | $8–$20 per treated sq ft |
| Watershed Protection administrative review | 90–180 days typical |
| Council variance application (if pursued) | 6–12 months + legal/consultant costs |
| Long-term BMP maintenance escrow / covenant | Required, project-specific |
Common mistakes
- ✕
Assuming the TCEQ WPAP is enough
An approved WPAP under 30 TAC §213 does not satisfy §25-8. Inside the Barton Springs Zone, Austin runs its own review and imposes stricter loading limits than the state. Both permits run in parallel and both must close before a building permit issues.
- ✕
Conflating the DWPZ with the SOS boundary
The Drinking Water Protection Zone is the larger western Austin watershed set; the SOS Ordinance only applies to the Barton Springs Zone subset. Applying SOS rules to Lake Austin or Bull Creek tracts overstates the requirement; missing SOS on a Sunset Valley-adjacent site understates it.
- ✕
Ignoring the net-site-area denominator
The IC cap is expressed as a percentage of net site area, which excludes critical environmental features, steep slopes, and required buffers. A parcel with a recharge feature or a 25%+ slope can lose 30–50% of gross acreage from the denominator before any IC is proposed.
- ✕
Forgetting the non-degradation baseline
Net-zero is measured against existing, not theoretical pristine, conditions for most sites — but redevelopment of a site that was historically overbuilt does not get credit for "going down." The baseline is the lesser of existing and §25-8-514 reference values; check it early.
- ✕
Betting on a Council variance
Council variances under SOS are politically fraught. Even when granted they carry deed restrictions that travel with the land forever and often reduce IC below the as-of-right cap elsewhere on the site. Treat variances as a last resort, not a design strategy.
Related rules
- TCEQ Edwards Aquifer WPAPState-level pre-construction permit that always runs alongside SOS on Barton Springs sites.
- Texas regulatory stackSOS is one of seven Texas layers TierraLens models — TPDES, karst ESA, RRC, and more.
- City of Austin Watershed ProtectionDepartment that reviews SOS water-quality plans and maintains the BSZ boundary data.
- Austin City Code (municode)Full text of §25-8 — the Environmental and Water Quality chapter.
Sources and authorities
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