The intent of Austin's drainage policy for stormwater management is to implement design principles and practices that control post-development runoff from all development such that no development will result in additional adverse flooding impacts in accordance with Chapter 25-7 of the Land Development Code.
(A) The owner or developer of property to be developed is responsible for the conveyance of all stormwater flowing through the property, including stormwater that:
(1) is directed to the property by other developed property; or
(2) naturally flows through the property because of the topography.
(B) Future upstream development shall be accounted for as determined under the Drainage Criteria Manual.
(C) If the construction or improvement of a storm drainage facility is required along a property line that is common to more than one property owner, the owner proposing to develop the property is, at the time the property is developed, responsible for each required facility on either side of the common property line.
(D) The responsibility of the owner proposing to develop the property includes the responsibility to dedicate or obtain the dedication of any right-of-way or easement necessary to accommodate the required construction or improvement of the storm drainage facility.
(E) If an owner of property proposes to develop only a portion of that property, a stormwater drainage facility to serve that portion of the property proposed for immediate development or use is required, unless the director determines that construction or improvement of a drainage facility outside that portion of the property to be developed is essential to the development or use of the property to be developed.
(F) The owner or developer shall provide adequate off-site drainage improvements to accommodate the full effects of the development. The city may assist the owner or developer in the acquisition of an interest in property necessary to provide an off-site improvement, if the owner or developer:
(1) by affidavit, certifies that a bona fide attempt to provide the off-site drainage improvements has not been successful; and
(2) provides an adequate guarantee that the owner or developer will:
(a) finance the entire cost of acquiring the necessary property interest; and
(b) retain full responsibility for construction of the required off-site improvement.
(A) In this section:
(1) COMMERCIAL DEVELOPMENT means all development other than Residential Development.
(2) COMMERCIAL BASIN means a required detention basin or appurtenance that receives stormwater runoff from a Commercial Development.
(3) DCM STANDARDS means the provisions in the Drainage Criteria Manual regarding maintenance of a required detention basin or appurtenance.
(4) RESIDENTIAL DEVELOPMENT means development of two dwelling units or less per lot.
(5) RESIDENTIAL BASIN means a required detention basin or appurtenance that receives stormwater runoff from a residential development.
(B) The record owner of a commercial development shall maintain the commercial basin serving the commercial development in accordance with the DCM standards, whether or not the commercial basin is located on the same property as the commercial development. The record owner shall provide the City proof of the right to access and maintain the commercial basin if it is not located on the same property as the commercial development.
(C) If more than one commercial development is served by a single commercial basin, the record owners of the commercial basin and all commercial developments served by the commercial basin shall be jointly and severally responsible for maintenance of the commercial basin in accordance with the DCM standards.
(D) The director may authorize an alternative arrangement for maintenance of a residential or commercial basin in accordance with the DCM standards. If an alternative arrangement is approved by the director, the City Attorney shall determine whether an agreement is necessary; the agreement must be approved by the City Attorney and filed of record.
(E) The City shall inspect each commercial basin that is not a subsurface basin at least once every three years to ensure that the commercial basin is being maintained in accordance with the DCM standards. If the commercial basin fails inspection requiring an additional inspection, the director may charge a re-inspection fee.
(F) The record owner of a subsurface commercial basin must provide the Watershed Protection Department with a maintenance plan and an annual report from a registered engineer verifying that the basin is in proper operating condition.
(G) Until the City accepts a residential basin for maintenance, the record owner(s) of the residential basin and the residential development served shall maintain the residential basin in accordance with the DCM standards.
(H) The City shall be responsible for maintenance of a residential basin only after the residential basin has been accepted for maintenance by the City. The City will accept a residential basin upon determining that it meets all requirements of the Drainage Criteria Manual.
Austin Texas Green Stormwater Infrastructure Maintenance Manual