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How the Regional Stormwater Management Program (RSMP) Changes Will Affect Your Austin Project in 2021

The payment structure for the RSMP and the Urban Watershed Structural Control Fund is changing soon. Here’s what you need to know.
Austin Stormwater Pond

Changes are coming to the Regional Stormwater Management Program (RSMP) and the Urban Watershed Structural Control Fund in Austin, Texas. Here’s what you need to know and how the changes may affect your development project.

Current RSMP Program

The RSMP allows developers in Austin, Texas to make a payment in lieu of constructing a detention pond or construct approved off-site drainage improvements. Participation is on a case-by-case basis when it can be demonstrated on-site detention is not needed.

The RSMP participation fee is primarily a factor of the appraised land value, proposed impervious cover, and approximate detention facility construction costs. Currently, there are two calculators, each with their own rate scales: one for single-family development and one for commercial/multifamily development. The appraised land value is currently capped at $40K per acre for single-family developments and is capped at $120K per acre for commercial/multifamily developments. A construction cost adjustment factor using the Engineering News Record Construction Cost Index Adjustment Factor with the base year of 2002 is applied to all RSMP calculations; the ENR AF is currently around 1.72. It is assumed that 5% of the site area is the required footprint for a detention facility.

Proposed Changes to RSMP

A 2018-2019 study was completed to update the RSMP participation cost calculator for both single-family and commercial/multifamily developments. The study focused on updating construction costs and providing a realistic value for the land cost component. Below is a summary of the proposed changes:

  • The cost per acre will no longer be capped, instead, a 20% reduction of the appraised land value will be applied as part of the RSMP land cost component.
  • The assumed footprint for detention will remain at 5% of the site area.
  • An impervious cover adjustment factor (ICAF) will be applied when the proposed impervious cover is lower than the City’s weighted average impervious cover (52.3%). This will provide a reduction in the participation fee for development with a proposed impervious cover below the City’s average. The ICAF will remain at 1 for sites that have a proposed IC which is above the City average. (No impact for development with IC greater than 52.3%.)
  • An overall cap of $440K per acre on the calculated payment for detention has been added to prevent a high land appraisal value from overestimating the on-site detention construction cost. This cap is intended to reflect the cost of a subsurface on-site detention vault commonly required in high land value dense urban areas.


The City is encouraging all stakeholders to provide any feedback on the proposed changes. A preliminary rules posting is expected this month (May 2020), and the new fee structure is expected to take effect for the fiscal year 2021 (October 2020).

In addition to RSMP fee calculation updates, RSMP participation is now part of the development application completeness check and formal review submission. A feasibility meeting must be held prior to completeness and a full RSMP application package must be provided with the formal submittal or the project will be rejected for U0 comments. The RSMP Feasibility Meeting Request form has been updated and is now the “RSMP Feasibility Determination Request Form”. Once submitted, RSMP staff will determine if a feasibility meeting will be scheduled or if on-site detention is required.

Austin Stormwater Pond
A stormwater pond currently under construction at a WGI project in Austin, Texas.

More Information

You can visit the City of Austin’s website for more details and information.

We’re Here For You

Don’t navigate these complicated rate structure changes alone. Contact WGI to speak with our Austin-based Stormwater and site development experts today. We’ll help you make sense of the changes and how they may affect your development projects in Austin.

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