Austin critical environmental features: the 150-foot buffer that can unbuild a lot

Last verified August 7, 2026 against the Austin Land Development Code · Kimbrough Gray · KiliGray Homes

Critical environmental features are bluffs, canyon rimrocks, caves, faults and fractures, seeps, sinkholes, springs and wetlands. Each carries a buffer zone of 150 feet from its edge, or between 150 and 300 feet for a point recharge feature. Construction is prohibited inside a buffer, and a residential lot may not include a feature, include its buffer, or lie within 50 feet of the feature.

Applies to: Any development or subdivision where a critical environmental feature is present. The residential lotting prohibition in §25-8-281(B) applies regardless of how large the tract is.

Eight kinds of feature

§25-8-1 defines critical environmental features as features "of critical importance to the protection of environmental resources", and lists them:

bluffs
canyon rimrocks
caves
faults and fractures
seeps
sinkholes
springs
wetlands

West and south-west Austin sits on karst. Caves, sinkholes and springs are not unusual there — they are among the ordinary reasons a plat fails.

This is the one provision on this hub that can make land unlottable. §25-8-281(B) does not restrict a residential lot containing a critical environmental feature. It prohibits it:

"A residential lot may not include a critical environmental feature or a critical environmental feature buffer zone and may not be located within 50 feet of a critical environmental feature."

Three prohibitions in one sentence — not the feature, not its buffer, and not within 50 feet of the feature. With a 150-foot default buffer, a single spring or sinkhole can remove a large area from residential lotting.

These two rules bite at different moments — and unlike impervious cover, the second one reaches a platted lot. §25-8-281(B) is a rule about creating lots: it is applied at subdivision, so on an already-platted lot that question has been settled one way or the other. But §25-8-281(C)(2) prohibits construction in a buffer, and §25-1-21 defines development to include "the construction or reconstruction of a building". That prohibition applies to a house on an existing lot regardless of whether a site plan is required.

This is the opposite of watershed impervious cover, where §25-8-61(B) expressly says the requirements do not restrict a single-family or duplex lot. There is no equivalent carve-out here.

The buffer is 150 feet — unless it is a point recharge feature

A buffer zone is established around every critical environmental feature.

Default: 150 feet from the edge of the feature.
Point recharge feature: the buffer coincides with the topographically defined catchment basin — with the distance from the feature edge being not less than 150 feet, not more than 300 feet, and calculated under the Environmental Criteria Manual.

A point recharge buffer is not a circle. It follows the shape of the catchment basin; the 150 and 300 foot figures are only a floor and a ceiling on how far it extends from the feature. Scaling a 300-foot radius off a plan would give the wrong answer in both directions.

What is prohibited inside a buffer

Three rules apply within any buffer zone under §25-8-281(C)(2):

the natural vegetative cover must be retained to the maximum extent practicable;
construction is prohibited; and
wastewater disposal or irrigation is prohibited.

That third item matters on a lot relying on on-site sewage — a drainfield cannot go in a buffer, which compounds the area a feature takes out of play.

Distance from the feature edge	What is allowed
Within 50 ft	No construction of any kind. No residential lot may even be located here.
50 ft to the buffer edge	Construction still prohibited except: a hiking trail; a recharge basin approved under §25-8-213 discharging to a point recharge feature; or an innovative runoff management practice approved under §25-8-151
Beyond the buffer	Ordinary development rules apply — but the lot still may not include any part of the buffer

From §25-8-281(B) and (C). The 50-foot line does two separate jobs: it is the minimum separation for a residential lot, and the point beyond which the three listed constructions become possible inside a buffer.

Point recharge features must be fenced. §25-8-281(C)(4) requires perimeter fencing with at least one access gate at the outer edge of the buffer zone for all point recharge features, complying with the Standard Specifications Manual. This is a permanent physical obligation on the finished site, not a construction phase measure.

Drainage has to be designed around them

Beyond the buffer rules, §25-8-281(A) imposes a design obligation on the whole development. Drainage patterns must be designed to:

protect critical environmental features from the effects of runoff from developed areas; and
maintain the catchment areas of recharge features in a natural state.

Special controls must be used where necessary to avoid erosion, sedimentation or high rates of flow. So a feature influences the site plan well outside its buffer — anything draining toward it is in scope.

This page does not tell you how features are identified. §25-8-281 governs what happens once a critical environmental feature is present. Who determines that something qualifies, and what survey work establishes it, sit elsewhere — and the point recharge buffer calculation is governed by the Environmental Criteria Manual, which we do not hold. If a feature is suspected on a tract, that assessment comes before any of this.

Common questions

What is a critical environmental feature in Austin?

Under §25-8-1, a feature of critical importance to the protection of environmental resources — including bluffs, canyon rimrocks, caves, faults and fractures, seeps, sinkholes, springs and wetlands.

How big is the buffer around a critical environmental feature in Austin?

150 feet from the edge of the feature by default. For a point recharge feature the buffer coincides with the topographically defined catchment basin, at not less than 150 feet and not more than 300 feet from the feature edge, calculated under the Environmental Criteria Manual.

Can you build on a lot with a sinkhole or spring in Austin?

Not as a residential lot containing it. §25-8-281(B) provides that a residential lot may not include a critical environmental feature or its buffer zone, and may not be located within 50 feet of the feature.

Is construction allowed inside a critical environmental feature buffer?

Generally no. Construction is prohibited within a buffer zone, as is wastewater disposal or irrigation, and natural vegetative cover must be retained to the maximum extent practicable. At least 50 feet from the feature edge, three exceptions become available — a hiking trail, an approved recharge basin discharging to a point recharge feature, and an approved innovative runoff management practice.

Do you have to fence a recharge feature in Austin?

Yes, for point recharge features. Perimeter fencing with at least one access gate must be installed at the outer edge of the buffer zone, complying with the Standard Specifications Manual.

Is a critical environmental feature buffer a circle in Austin?

Not for a point recharge feature. That buffer coincides with the topographically defined catchment basin, with 150 and 300 feet acting only as the minimum and maximum distance from the feature edge. The ordinary 150-foot buffer is measured from the edge of the feature.

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We do this research ourselves on every project we take on — zoning, floodplain, watershed, trees, whether it is a legal lot. Send us an address and we will run it and tell you what we find. It works the same whether you own a vacant lot, a house you are thinking of adding a unit to, or a house you are thinking of replacing. No charge and no strings, and if it is a bad lot we will say so.

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We are homebuilders, not the City of Austin. This page explains how we read the code in practice — it is not legal advice and it is not an official determination. Always confirm with Austin Development Services before you rely on it for a project. The authoritative text is the Austin Land Development Code; permitting questions go to Austin Development Services Department.