C20-2023-045 Site Plan Lite Phase 2 & Infill Plats
C20-2023-045 Site Plan Lite Phase 2 & Infill Plats
Amend City Code Title 25 (Land Development Code) related to development regulations applicable to residential re-subdivisions and multi-family residential site development of five to sixteen units.
Background
Site Plan Lite Phase 2
On December 1, 2022, City Council approved Resolution No. 20221201-048, initiating Land Development Code (“LDC”) amendments to facilitate the creation of missing middle housing by scaling site plan review requirements for residential projects of three to sixteen units. As Phase 1 of the project, Council adopted Ordinance No. 20230720-158 on July 20, 2023, creating a site plan exemption for projects having four or fewer residential units.
These proposed amendments would complete Council’s direction from Resolution No. 20221201-048 by establishing a more streamlined review process for projects of 5 to 16 units located on a single lot.
Infill Plat Process
On May 4, 2023, Council approved Resolution No. 20230504-023 initiating LDC amendments to facilitate the creation of infill lots within existing residential subdivisions, with the goal of expanding opportunities for “fee simple” ownership and easing the impact of non-zoning regulations on residential re-subdivisions. The proposed amendments would achieve this objective by modifying non-zoning regulations for infill development, thereby establishing a more streamlined review process.
Summary of Proposed Amendment
The proposed amendments remain under review and may be further refined. However, the core ideas for both proposals are well-developed and calibrated to achieve Council’s goals by right-sizing non-zoning regulations applicable to infill development, which will facilitate additional housing opportunities consistent with the HOME-1 and HOME-2 amendments.
- Modified Drainage Standards
The proposal for both Infill Plats and Site Plan Lite Phase 2 would eliminate the requirement to provide onsite detention facilities or drainage analyses for development below 8,000 square feet of impervious cover, which matches the cutoff point below which development is not required to provide water quality controls under current regulations. The new requirements described more fully below would enable significant improvements to the review process and reduce construction costs by eliminating “micro-ponds” currently required for many small-scale infill projects.
Following are some additional features of the proposal:
Except for re-subdivisions of two-unit, duplex, or three-unit uses, development that exceeds 4,000 square feet of new impervious cover would be required to provide a simplified drainage plan demonstrating that stormwater runoff will be discharged into an existing storm drainage system or right-of-way. This would be substantially easier and less costly than providing onsite detention facilities or drainage studies while still ensuring a basic level of drainage review for development that exceeds this impervious cover threshold.
The new process would be limited to development on sites of no more than one acre consisting of either 5-16 units on a single lot or resubdivisions that create no more than eight lots within a residentially platted subdivision.
- Revised Impervious Cover Assumptions
In regulating subdivisions, the Land Development Code relies on impervious cover assumptions that estimate how much impervious cover is likely to be developed based on lot size. The assumptions play a critical role in calibrating water quality and drainage requirements since the creation of lots does not generate actual impervious cover the way that building permits or site plans do.
Current code assumes 2,500 square feet of impervious cover for any lot less than 10,000 square feet in size, which is unrealistically high for smaller lots. The proposed amendments would tie impervious cover assumptions directly to the impervious cover allowed for a lot under base zoning regulations, which is more realistic and will substantially increase the number of small lots that can be included in a subdivision without triggering onsite detention or water quality controls.
- Small Project Site Plan
The “Small-Project Site Plan” is an intermediate review path well-suited for projects that can’t feasibly be reviewed as site plan exemptions but aren’t subject to the full range of regulations typically reviewed for a site plan. They are subject to reduced fees, streamlined submittal requirements, and quicker review times.
The proposed amendments would classify development of 5-16 units on a lot as a “small project” if it satisfies the requirements for modified drainage review discussed above. This is appropriate to the level of review required for this tier of “Site Plan Lite,” which will not require drainage or water quality review but may trigger zoning and Building Code regulations that cannot be reviewed through the standard site plan exemption or residential review process.
Case Manager Contact
Brent Lloyd, Development Services Department, Brent.Lloyd@austintexas.gov