11 C20-2023-045 - Site Plan Lite Phase 2 & Infill Lots Staff Report — original pdf

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Case No. C20-2023-045 Planning Commission: August 27, 2024 ORDINANCE AMENDMENT REVIEW SHEET Amendment: C20-2023-045 | Site Plan Lite, Phase 2 & Infill Plats Amendment Introduction: This staff report discusses amendments to the Land Development Code (“LDC”) proposed in response to two separate council initiatives intended to facilitate construction of infill housing: Resolution No. 20221201-048 (“Site Plan Lite”) and Resolution No. 20230504-023 (“Infill Plats”). These amendments, which will be included in a single ordinance, seek to better calibrate non-zoning regulations and review procedures to the scale of “missing middle” housing. The report also describes changes initiated or under consideration by individual departments to address non-LDC related challenges to development of missing middle housing, including amendments to administrative criteria manuals and improvements to existing review procedures. Amendment Background: — Site Plan Lite, Phase 2 On December 1, 2022, the City Council passed Resolution No. 20221201-048 initiating LDC amendments to better scale site plan review for residential projects of three to sixteen units located on a single lot. For Phase 1, Council adopted Ordinance No. 20230720-158 on July 20, 2023, creating a site plan exemption for projects of four or fewer residential units. This change, coupled with subsequent passage of the first HOME ordinance, has enabled staff to conform the review process for 3-4 unit residential projects more closely to the process used for one and two-unit projects. For Phase 2, staff’s proposed amendments would modify applicable drainage regulations and adopt a new “small project” classification to enable further streamlining the review process for projects of five to sixteen units. These amendments, coupled with additional department- initiated changes, will make it easier to construct smaller multi-family projects on appropriately zoned lots. — Infill Plats On May 4, 2023, Council approved Resolution No. 20230504-023 initiating LDC amendments to facilitate the creation of infill lots and expand opportunities for “fee simple” ownership within existing residential subdivisions. Staff’s proposed amendments would help to further this objective by modifying applicable drainage regulations, which are a significant cost driver, and changing how impervious cover is Case No. C20-2023-045 | Page - 1  calculated to allow re-subdivisions to include a greater number of lots. In tandem with additional department-initiated changes, these amendments will better calibrate regulations applicable to small-lot single-family uses as authorized by the second HOME ordinance. Case No. C20-2023-045 Planning Commission: August 27, 2024 — Department-level Improvements Aside from drainage regulations codified in LDC Chapter 25-7 (Drainage), most of the other regulatory challenges highlighted by Council’s resolutions on infill housing are related primarily to administrative criteria manuals and department-level review procedures. Since these aspects of the development process also affect infill development, Appendix A of this report describes several improvements planned or under review by DSD’s partner departments. This work will remain ongoing following Council action on the proposed code amendments and will be informed by feedback received throughout the public process, as well as review by the Technical Advisory Review Panel (TARP). One major proposal in this category, to be initiated by the Watershed Protection Department (WPD), is an amendment to the Drainage Criteria Manual (DCM) that will significantly reduce the circumstances in which development is required to connect to an existing storm drain system. This proposal responds to stakeholder feedback received at a DSD-led testing session that took place on June 6, 2024. Summary of Proposed Code Amendments: Modified Drainage Regulations I. — Background LDC Sec. 25-8-211(B)(3) exempts development with up to 8,000 square feet of impervious cover from the requirement to provide water quality controls on sites located outside of the Barton Springs Zone. However, the code provides no similar exemption for drainage regulations under Chapter 25-7 (Drainage). This means that, under current code, infill re-subdivisions and multi-unit site plans are required to meet detention standards similar to those required for large-scale multi-family and commercial projects. The amendments proposed by staff would tailor drainage regulations more closely to the scale and intensity of residential infill projects. {intentionally left blank} Case No. C20-2023-045 | Page - 2  — Case No. C20-2023-045 Planning Commission: August 27, 2024 Summary of Proposed Amendments The table below summarizes proposed amendments to Chapter 25-7 (Drainage): Project Type Limitations Drainage Requirements Infill Re-Subdivision Site is no greater than 0.25 acres Site is over 0.25 acres, but no greater than one acre Limited to 5-16 dwelling units and site may not exceed 0.50 acres Site Plan — Applicant must provide a Drainage Plan demonstrating that, without altering natural topography, stormwater runoff will be discharged to: (1) an existing storm drainage system; or (2) into right-of-way. — Effect of Proposed Amendments No project meeting the “Limitations” described in the second column, above, will be required to provide a drainage study or onsite detention facilities. In cases where a drainage plan is required, the level of complexity and cost will be substantially less than participation in the Regional Stormwater Management Program administered by WPD. As described below, these proposed amendments will substantially reduce the impacts of drainage regulations on infill development throughout the City. Infill Plats 1. — Lots no Greater Than a Quarter (0.25) Acre. Both HOME 1 & 2 focused on the feasibility of adding density to existing single lots, either through more units on a single lot or re-subdivision. These proposed amendments will significantly reduce the impact of drainage regulations on projects re-subdividing into small lot sizes, thereby aligning infill re-subdivision requirements more closely with requirements applied through the residential review process. As shown in the diagram to the left, the proposed amendments would allow over 75% of HOME eligible lots under an Case No. C20-2023-045 | Page - 3  Case No. C20-2023-045 Planning Commission: August 27, 2024 acre in size1 to re-subdivide without providing drainage studies or onsite detention facilities. — Lots Greater than a Quarter Acre, But No Greater than One Acre The proposed amendments establish a streamlined drainage review process for lots that are greater than a quarter acre, but do not exceed one acre. Under this process: • Neither drainage studies nor onsite detention facilities would be required if applicants provide a drainage plan demonstrating that stormwater runoff is discharged to a storm drain system or right-of-way. • The drainage plan would not have to be submitted by a registered engineer. • No payment would be required under the Regional Storm Management Program (RSMP). If lots within this size range require grading to successfully drain to a storm drain system or right-of-way, an applicant would have to submit a drainage plan by a licensed engineer and make payment under RSMP but would not be required to undertake full drainage review or provide onsite detention. If a site cannot successfully demonstrate that runoff discharges to a storm drain system or right-of-way, full drainage review and onsite detention are required to meet the “no adverse impact” standard under Chapter 25-7 (Drainage). 2. Site Plan Lite The “Site Plan Lite” initiative is intended to facilitate “missing-middle” style housing: i.e., small-to-medium sized multi-family developments that offer greater density than a traditional single-family or condo development, but less density than a large, structured apartment building. As shown in the table on page 5, the MF-1 (Limited Density), MF-2 (Low Density), and MF- 3 (Medium Density) zoning districts allow 2 a density of 5-16 units consistent with the goals of Site Plan Lite, Phase 2. As sites approach an acre in size, lots zoned MF-2 and MF-3 are capable of developing more units than is permitted by Site Plan Lite. Utilizing Site Plan Lite for those zones above an acre is unlikely because it would require substantial under-utilization of site area. 1 A quarter of an acre (10,890 sf) ensures that the minimum lot area for SF-1 and SF-2/SF-3 (10,000 sf and 5,750 sf, respectively) can be subdivided without drainage review. A quarter acre lot can re-subdivide into 6 small lot single-family lots. 2 The number of allowed units is determined by comparing the size of a lot to the minimum site area per dwelling unit. This number differs from the number of developable units which is dependent on individual site features, design choices, zone-specific regulations, and other regulatory requirements. Allowable units provide reference points for desired and appropriate densities but are not a guaranteed level of development. Case No. C20-2023-045 | Page - 4  Case No. C20-2023-045 Planning Commission: August 27, 2024 Half Acre One Acre Allowed Units by Zone and Lot Size Min. Site Area per Unit Type MF-1 MF-2 MF-3 MF-1 MF-2* MF-3* Efficiency One-Bedroom Two+ Bedrooms 8 7 6 13 10 9 18 14 12 17 14 12 27 21 18 36 29 24 Of all lots zoned MF-1, MF-2, and MF-3, over 80% are under a half-acre in size and would be eligible for the new modified drainage regulations. An additional 5.8% are eligible for the modified RSMP regulations that WPD will bring forward following possible action on this amendment. — Half Acre or Less Site plan applications for lots 1/2-acre or less would be eligible for the same drainage requirements as those outlined above for infill re-subdivisions between 1/4-acre and 1-acre:   If a drainage plan can demonstrate that runoff is discharged to a storm drain system or right-of-way, no RSMP payment is required. If a grading plan is required to demonstrate that runoff is discharged to a storm drain system or right-of-way, a licensed engineer must prepare the drainage plan and an RSMP payment is required. Case No. C20-2023-045 | Page - 5  Case No. C20-2023-045 Planning Commission: August 27, 2024  If runoff cannot be directed to a storm drain system or right-of-way, full drainage review and detention is required to demonstrate “no adverse impact” under Chapter 25-7 (Drainage). — Greater than Half an Acre, but No Greater than One Acre Site plan applications for multi-family lots between 1/2-acre and 1-acre may provide an engineered grading plan to demonstrate runoff to a storm drain system or right-of-way and pay an RSMP payment. If a site cannot successfully demonstrate that the runoff discharges to a storm drain system or right-of-way, full drainage review and detention are required. Modified Impervious Cover Assumptions II. — Background LDC Sec. 25-8-64 (Impervious Cover Assumptions) sets forth assumptions about how much impervious cover is likely to be developed based on lot size. The assumptions play a critical role in applying water quality and drainage regulations to proposed subdivisions, since the creation of lots does not generate actual impervious cover the way that building permits or site plans do. Under current LDC Sec. 25-8-64, all lots of up to 10,000 square feet in size are assumed to have 2,500 square feet of impervious cover. This assumption is unrealistically high for residential lots under 5,750 square feet, which are limited by zoning to 40-45 percent impervious cover. It also has the effect of triggering water quality controls for most residential subdivisions of more than three lots, since the exemption in Sec. 25-8- 211(B)(3) is capped at 8,000 square feet of assumed impervious cover as described above. — Summary of proposed amendments To provide a more realistic and workable assumption for lots of at least 1,800 square feet but less than 5,750 square feet (i.e., small lots), the proposed amendments would use the impervious cover allowed under applicable zoning regulations as the assumed impervious cover in Sec. 25-8-64. When subdividing into smaller lot sizes, this change will allow applicants to create more lots without exceeding the 8,000 square feet of assumed impervious cover that triggers water quality and detention requirements. — Effect Tying the assumed impervious cover to the zoning impervious cover will ensure that the maximum amount of feasible small lots can be created while also assuring that the impervious cover assumed at subdivision will appropriately account for the anticipated development. For example, under the proposed amendments, a subdivision could create up to nine (9) SF-3- zoned lots of 1,800 square feet without triggering water quality or Case No. C20-2023-045 | Page - 6  detention requirements, but only three (3) under current assumptions. Case No. C20-2023-045 Planning Commission: August 27, 2024 Small Project Site Plan III. — Background LDC Sec. 25-5-3 (Small Projects), commonly referred to as “Small-Project Site Plans,” establishes 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 at site plan. — Summary of proposed amendments The proposed amendments would establish a new small-project category for developments of 5 to 16 units that are exempt from onsite detention requirements under the standards discussed in Part I (Modified Drainage Regulations), 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 for through the standard site plan exemption or residential review process. — Effect Small-Project Site Plans are subject to reduced fees, streamlined submittal requirements, and quicker review times. Applications for small projects, unlike standard site plans, are not subject to notification requirements. Due to these improved efficiencies, small multifamily projects will be able to navigate the development review process more quickly and economically. Staff Recommendation: Staff supports the proposed revisions to the Land Development Code and requests a 90-day delayed implementation to provide the time necessary for departmental process updates and staff training. Board and Commission Action: April 1, 2024: To be reviewed by the Codes and Ordinances Joint Committee. May 1, 2024 & August 21, 2024: To be reviewed by the Environmental Commission. August 27, 2024: A public hearing will be held by the Planning Commission. Council Action: September 12, 2024: A public hearing will be held. Sponsor Department: Development Services Department City Staff: Brent Lloyd, DSD, Development Officer Case No. C20-2023-045 | Page - 7  ATTACHMENT A Cas No. C20-2023-045 Planning Commission: August 27, 2024 DEPARTMENT-LEVEL IMPROVEMENTS Below is a summary of important department-level changes that would help to support development under the proposed Infill Plat and Site Plan Lite amendments. The improvements are responsive to stakeholder feedback received at a DSD-led testing session held on June 6, 2024, as well as ongoing efforts of individual departments that participated in the testing. 1. Watershed Protection Department (WPD) Drainage Criteria Manual (DCM) Sec. 1.2.3.C – Street Drainage This DCM provision requires proposed development to connect to an existing storm drain system if it’s located within 550 feet. While WPD grants waivers where appropriate, stakeholder feedback indicates that compliance with this requirement may in some instances be cost prohibitive for infill development. In response to these concerns, WPD has stated its intent to initiate amendments to DCM Sec. 1.2.3.C along the following lines:  Connection to an existing storm drain system would only be required if a project is located within 300 feet, rather than 550 feet.  Regardless of distance, no connection would be required for projects that are limited to residential use and: o The existing lot is 0.50 acres or less in gross site area; or o The existing lot is over 0.50 acres, but no greater than one acre, and the applicant provides necessary calculations indicating that the street, gutter, and storm drain inlet contains the 100-year fully developed flow rates for the entire drainage area that drains to the existing storm drainage system. While the details of these changes remain under review, WPD has stated its intent to initiate them at a future DCM amendment cycle following Council action on the proposed Site Plan Lite and Infill Plats ordinance. Review by the Technical Advisory Review Panel (TARP) would also be provided. DCM Sec. 1.2.2.G – Detention Alternatives WPD has stated its intent to consider potential improvements to the Regional Stormwater Management Program (RSMP) to benefit infill projects that exceed the cutoffs for streamlined drainage review under the newly proposed LDC Sec. 25-7-67 (Modified Drainage Standards for Residential Infill), as summarized in the staff report. In particular, WPD plans to initiate a DCM amendment that would allow “Site Plan Lite” projects of 5-16 units to participate in RSMP if they do not exceed one acre in gross site area. Attachment A (Case No. C20-2023-045) | Page – 1  ATTACHMENT A Cas No. C20-2023-045 Planning Commission: August 27, 2024 2. Transportation & Public Works Department (TPW) In response to stakeholder feedback and TPW’s ongoing efforts to improve the review process, the department has stated its intent to initiate amendments to the Transportation Criteria Manual (TCM) to reduce the need for unnecessary waiver requests when permitting a project under the proposed Infill Plat and Site Plan Lite amendments. These amendments include:  Reducing the width for a “Minor Driveway” to 10 feet  Allowing ribbon or “Hollywood” strips as a permitted driveway design; and  Reducing requirements for Joint Use Access easements. TPW has also stated its intent to continue improving the review process to better meet the needs of infill development. Potential changes include: • Improving the review process for waiver requests from driveway spacing standards so that technical review is only required when necessary and more requests can be considered informally, without additional review time. • Updating the “Site Plan Master Comment Report” to clarify that back-of-curb pedestrian improvements under the LDC are required, but TCM improvements are optional. • Where street impact fees are assessed, provide the MAX/RP calculation whenever dedication of ASMP-compliant right-of-way dedication is requested in a Master Comment Report. • Work with review staff to clarify applicability of street tree requirements and ensure that they’re not applied to existing streets. 3. Austin Water (AW) AW has expressed its willingness to explore potential improvements to the SER process to help applicants achieve greater certainty on likely infrastructure costs earlier in the development process. These measures may emphasize greater education regarding the SER process and options for obtaining earlier determinations, as well as guidelines for applicants considering concurrent SER/SP review. Additionally, AW is aware that greater use of utility easements may be necessary to facilitate development of small-lot single-family uses under HOME-2. Attachment A (Case No. C20-2023-045) | Page – 2  Affordability Impact Statement Infill Plats & Site Plan Lite, Phase 2 Initiated by: Resolution No. 20221201-048, 20230504-023 Case number: C20-2023-045 Date: July 5, 2024 Proposed Regulation The proposed amendments would do the following: Infill Plats • Provides small-scale residential developments with a streamlined subdivision review process to facilitate fee-simple ownership of lots as an alternative to condominium regimes. • Aligns impervious cover assumptions used in the streamlined subdivision review with impervious cover limits imposed by zoning regulations, which will provide more flexible subdivision options, allowing landowners to create smaller lots without triggering full subdivision review. • The modified drainage standards are limited to applications that meet the following criteria: • Less than one acre in site area; o Not located within the Wildland Urban Interface; o o Does not require a plat vacation. Is within a previously platted residential subdivision; and • Projects under a quarter-acre are not required to provide a drainage study or onsite detention. • Projects between a quarter-acre and one acre must provide a drainage plan demonstrating that, without altering natural topography, stormwater will discharge to an existing storm drainage system or right-of-way. Site Plan Lite, Phase 2 • The modified drainage standards are limited to applications that meet the following criteria: o Less than a half-acre in site area; and o 5 to 16 units on a single lot. • Qualifying projects must provide a drainage plan demonstrating that, without altering natural topography, stormwater will discharge to an existing storm drainage system or right-of-way. • Establishes a new “small-project” category for developments of 5 to 16 units that qualify for the modified drainage standards, streamlining the review process with shorter review times and reduced fees. Land Use/Zoning Impacts on Housing Costs The proposed changes would have a positive impact on housing costs by facilitating the delivery of missing middle projects through a less onerous permitting process and by expanding options for “fee simple” ownership of units on separate lots rather than condominium regimes. Like Home I and Home II, this housing strategy is aimed at increasing attainable housing options for middle-income Austinites, which is supported by many of the Strategic Housing Blueprint and Imagine Austin Goals to encourage diverse housing types throughout Austin. The modified drainage standards apply only to areas outside the Wildland Urban Interface (WUI). However, further analysis and discussion are necessary to determine if these standards are entirely unavailable in all proximity zones within the WUI or only in areas with the highest fire hazard risk, depending on the structure's distance from the wildland. Impact on Development Cost The proposed changes would have a positive impact on development costs by potentially reducing fees and time associated with replatting and permitting. When the process is fully implemented, requiring changes to applications and review procedures, staff anticipates a quicker and easier review process. Impact on Affordable Housing The proposed changes would have a positive impact on affordable housing. The proposed changes would make it easier for the City and affordable housing developers to reduce costs associated with re-subdivision and permitting and generate more affordable housing units. City Policies Implemented  Imagine Austin: Land Use and Transportation Action 2: Promote diverse infill housing such as small- scale apartments, smaller-lot single-family houses, town and row houses, and garage apartments that complement and enhance the character of existing neighborhoods.  Austin Strategic Housing Blueprint Action: Allow the Development of Smaller Houses on Smaller Lots  Austin Strategic Housing Blueprint Action: Better Utilize Land for Affordable Housing  Austin Strategic Housing Blueprint Action: Preserve and Create Ownership Options for Households at 80% to 120% MFI Other Housing Policy Considerations  Infill-plat amendments will enable an easier process for applicants to subdivide into smaller lot sizes proposed in HOME-2 amendments. The amendments will also support an easier process for creation of flag lots under revised requirements proposed in HOME-2. Manager’s Signature ________ __________ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 PLANNING COMMISSION VERSION TWO WORKING DRAFT-SUBJECT TO CHANGE August 27th, 2024 ORDINANCE NO. ____________ AN ORDINANCE AMENDING CITY CODE SECTIONS 25-8-64 AND 25-5-3 AND CREATING A NEW CITY CODE SECTION 25-7-67 RELATED TO DEVELOPMENT REGULATIONS APPLICABLE TO RESIDENTIAL RE- SUBDIVISIONS AND DEVELOPMENT APPLICATIONS AND DEVELOPMENT APPLICATIONS FOR MULTI-FAMILY RESIDENTIAL SITE DEVELOPMENT OF FIVE TO SIXTEEN UNITS. BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF AUSTIN: PART 1. Subsection (B) of City Code Section 25-5-3 (Small Projects) is amended to read: (B) The following are small projects: (1) construction of a building or parking area if the proposed construction: (a) does not require a variance from a water quality regulation; (b) does not exceed 5,000 square feet of impervious cover; and (c) the construction site does not exceed 10,000 square feet, including the following areas: (i) construction; (ii) clearing; (iii) grading; (iv) construction equipment access; (v) driveway reconstruction; (vi) temporary installations, including portable buildings, construction trailers, storage areas for building materials, spoil disposal areas, erosion and sedimentation controls, and construction entrances; (vii) landscaping; and (viii) other areas that the director determines are part of the construction site; 8/16/2024 Page 1 of 4 COA Law Department 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 PLANNING COMMISSION VERSION TWO WORKING DRAFT-SUBJECT TO CHANGE August 27th, 2024 (2) (3) construction of a storm sewer not more than 30 inches in diameter that is entirely in a public right-of-way or an easement; construction of a utility line not more than eight inches in diameter that is entirely in a public right-of-way; (4) construction of a left turn lane on a divided arterial street; (5) construction of street intersection improvements; (6) widening a public street to provide a deceleration lane if additional right- of-way is not required; (7) construction of five to 16 dwelling units that meet all applicable requirements for review under Section 25-7-67 (Modified Drainage Standards for Residential Infill); (8[7]) depositing less than two feet of earth fill, if the site is not in a 100-year floodplain and the fill is not to be deposited within the dripline of a protected tree; (9[8]) construction of a boat dock as an accessory use to a single-family residential use, duplex residential use, two-family residential use, or secondary apartment special use if shoreline modification or dredging of not more than 25 cubic yards is not required; or (10[9]) construction of a retaining wall, if the wall is less than 100 feet in length and less than eight feet in height, and the back fill does not reclaim a substantial amount of land except land that has eroded because of the failure of an existing retaining wall; (11[10]) minor development that the director determines is similar to that described in Subsections (B)(1) through (9) of this section; (12[11]) the replacement of development that is removed as a result of right-of- way condemnation; and (13[12]) the construction of a telecommunications tower described in Subsection 25-2-839(F) or (G) (Telecommunication Towers). 8/16/2024 Page 2 of 4 COA Law Department  PLANNING COMMISSION VERSION TWO WORKING DRAFT-SUBJECT TO CHANGE August 27th, 2024 PART 2. City Code Chapter 25-7 (Drainage) is amended to add a new Section 25-7-67 (Modified Drainage Standards for Residential Infill) to read: § 25-7-67 MODIFIED DRAINAGE STANDARDS FOR RESIDENTIAL INFILL. (A) This section applies to: (1) a resubdivision that: (a) (b) (a) (b) does not exceed a gross site area of one acre; includes only land within a subdivision that was originally platted as a residential subdivision; and (c) does not require a plat vacation; and (2) a site plan that: does not exceed a gross site area of 0.50 acres; and is limited to development of 5 to 16 dwelling units on a legal lot or tract. (B) Except as provided in Subsections (C) and (D), an applicant is not required to provide infrastructure, studies, or analyses to demonstrate a development application complies with Section 25-7-61 (Criteria for Approval of Development Applications), Section 25-7-151 (Stormwater Conveyance and Drainage Facilities), or Section 25-7-152 (Dedication of Easements and Right-of-Way) if: (1) The application is a resubdivision that does not exceed a gross site area of 0.25 acres; or (2) The applicant provides a drainage plan demonstrating that, without altering natural topography, all stormwater runoff from the development will be discharged: to an existing storm drainage system; or (a) (b) into right-of-way. 8/16/2024 Page 3 of 4 COA Law Department 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85  PLANNING COMMISSION VERSION TWO WORKING DRAFT-SUBJECT TO CHANGE August 27th, 2024 (C) A development application must demonstrate all proposed improvements will be outside the erosion hazard zone, unless protective works are provided as prescribed in the Drainage Criteria Manual. (D) The owner of real property proposed to be developed shall be required to provide an easement for stormwater flow to the limits of the 100-year floodplain, as prescribed in the Drainage Criteria Manual. PART 3. Subsection (B) of City Code Section 25-8-64 (Impervious Cover Assumptions) is amended to read: (B) Except as provided in Subsection (C): for each lot greater than three acres in size, 10,000 square feet of impervious cover is assumed. for each lot greater than one acre and not more than three acres in size, 7,000 square feet of impervious cover is assumed; for each lot greater than 15,000 square feet and not more than one acre in size, 5,000 square feet of impervious cover is assumed; for each lot greater than 10,000 square feet and not more than 15,000 square feet in size, 3,500 square feet of impervious cover is assumed; [and] for each lot greater than 5,750 square feet and not more than 10,000 square feet in size, 2,500 square feet of impervious cover is assumed[.]; and (6) for each residential lot not more than 5,750 square feet in size, the amount of impervious cover assumed is; (a) the maximum amount of impervious cover allowed under the applicable zoning district regulations; or (b) for lots in the extraterritorial jurisdiction, 2,500 square feet of impervious cover. (1) (2) (3) (4) (5) 8/16/2024 Page 4 of 4 COA Law Department 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116