Austin water quality controls: when you need one, and who actually does

Last verified August 6, 2026 against the Austin Land Development Code · Kimbrough Gray · KiliGray Homes

Water quality controls are required for all development in the Barton Springs Zone, and elsewhere where new and redeveloped impervious cover exceeds 8,000 sq ft or the development is in a water quality transition zone. Single-family and duplex lots are exempt.

Applies to: Development in Austin. The requirement attaches to a residential subdivision as a whole rather than to individual single-family or duplex lots.

If you are building one or two houses, this probably is not your problem. §25-8-211(D) states that the water quality control requirements "do not require water quality controls on a single-family or duplex lot but apply to the residential subdivision as a whole". The obligation sits with the subdivision, not the lot. Unless you are in the Barton Springs Zone, where §25-8-211(A) requires controls for all development with no threshold and no lot-level exemption.

Four triggers, and one of them is geographic

§25-8-211 splits the question by watershed.

In the Barton Springs Zone — required for all development. Full stop. No square footage threshold, and the subdivision-level exemption in (D) does not rescue you, because (A) is not qualified by it.

Everywhere else, controls are required where the development:

is located in a water quality transition zone;
is a golf course, play field or similar recreational use, if fertilizer, herbicide or pesticide is applied; or
has new and redeveloped impervious cover exceeding 8,000 sq ft.

Note the third one carefully. It is the total of new and redeveloped impervious cover, not new cover alone. On a redevelopment site where existing paving is being replaced, that existing area counts toward the 8,000 — which is often the difference between crossing the threshold and not.

One thing every project must do. §25-8-211(C): all new development must provide for removal of floating debris from stormwater runoff. That one carries no threshold and no exemption — it applies whether or not a structural control is required.

Paying instead of building one — urban watersheds only

§25-8-214 sets up a fee route, and its availability depends on where you are.

In an urban watershed, an applicant may request approval to deposit a nonrefundable cash payment with the City instead of providing the required controls, on a formula set by council. The director decides the request against standards in the Environmental Criteria Manual, and the money goes into the Urban Watersheds Structural Control Fund — which pays for facilities identified and prioritised in an Urban Watersheds Structural Control Plan, reviewed annually by the Environmental Commission.

So it is not a waiver. It is a contribution to a control being built somewhere the City judges more useful.

Outside urban watersheds the equivalent route is much narrower: under §25-8-214(F) it is available only for a public mobility project in the right-of-way in a suburban, water supply suburban or water supply rural watershed. A private development in those watersheds builds the control.

Redevelopment in an urban watershed may get City money

§25-8-215 is short and easy to miss. A person who redevelops property in an urban watershed and is required to construct a water quality control may qualify for cost participation by the City — either for:

construction of the water quality control; or
the optional payment instead of construction under §25-8-214.

It is a "may qualify", not an entitlement, and the section does not set out the criteria. But on an urban-watershed redevelopment that crosses the 8,000 sq ft threshold it is worth asking about before assuming the full cost falls on the project.

The roadway carve-out is narrower than it sounds

§25-8-211(E) exempts a roadway improvement with less than 8,000 sq ft of new impervious cover — but then defines "roadway improvements" restrictively. For this purpose they are limited to:

intersection upgrades;
low-water crossing upgrades;
additions for bicycle lanes; and
additions for mass transit stops.

A new street serving a subdivision is not on that list, and does not get the carve-out. Note too that this limb counts new impervious cover only, unlike the general (B)(3) threshold which counts new and redeveloped together.

Where this actually lands

For a single house or a duplex, nowhere — outside the Barton Springs Zone. The exemption in §25-8-211(D) is clean, and the obligation belongs to whoever platted the subdivision. That is worth knowing when a client is told they need a pond on a standard SF-3 lot.

It changes on a resubdivision or a small multi-lot development, where the subdivision is the project. There the 8,000 sq ft of new and redeveloped impervious cover is the number to test early, and on a few lots' worth of houses and driveways it is closer than people expect.

In the Barton Springs Zone the analysis stops at (A). All development, no threshold — and that sits alongside the 15% impervious cover cap and the SOS pollutant loading requirements, which are the harder constraints anyway.

Common questions

Do I need a water quality control for a single house in Austin?

Not on a single-family or duplex lot — §25-8-211(D) applies the requirement to the residential subdivision as a whole instead. The exception is the Barton Springs Zone, where controls are required for all development.

What triggers a water quality control in Austin?

All development in the Barton Springs Zone. Elsewhere: being in a water quality transition zone, a golf course or play field where fertilizer or pesticide is applied, or new and redeveloped impervious cover exceeding 8,000 sq ft.

Is the 8,000 sq ft threshold new impervious cover only in Austin?

No. §25-8-211(B)(3) counts the total of new AND redeveloped impervious cover. Existing paving being replaced counts toward the threshold.

Can I pay instead of building a water quality control in Austin?

In an urban watershed, yes — you may request approval to deposit a nonrefundable cash payment into the Urban Watersheds Structural Control Fund. Outside urban watersheds that route is limited to public mobility projects in the right-of-way.

Does Austin help pay for water quality controls?

It may. §25-8-215 provides that a person redeveloping property in an urban watershed who must construct a control may qualify for City cost participation, either for the construction or for the optional payment instead.

Does every Austin project have to handle floating debris?

Yes. §25-8-211(C) requires all new development to provide for removal of floating debris from stormwater runoff, with no threshold or exemption.

Send us an address and we will tell you what we find

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.

Send us an address

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.