21 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: October 22, 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. Revisions to Original Proposal: Following the Planning Commission’s public hearing on August 27, 2024, staff continued to meet with stakeholders to discuss ways of improving the proposal to better address their concerns. As a result, staff’s proposal includes the following changes: • Under the revised proposal, residential re-subdivisions of up to 11,500 square feet are exempt from drainage review. This will provide greater flexibility than the originally proposed cap of a quarter-acre (10,890 square feet). • The Transportation and Public Works Department (TPW) is instituting a streamlined process for approving relief from right-of-way dedication requirements, which will make the process easier and quicker for most infill projects. • The Parks and Recreation Department (PARD) has committed to streamlining the process for approving payment of a fee-in-lieu of parkland dedication for infill projects that meet certain criteria, with the goal of greater predictability and a quicker review process. These changes are discussed in more detail throughout this report and, for easy reference, are flagged as “[UPDATED] or “[NEW].” {intentionally left blank} Case No. C20-2023-045 | Page - 1 Case No. C20-2023-045 Planning Commission: October 22, 2024 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 “HOME-1” ordinance, has enabled staff to conform the review process for three to four-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 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 “HOME-2” ordinance. — 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 qualifying development is required to connect to an existing storm drain system. Case No. C20-2023-045 | Page - 2 Case No. C20-2023-045 Planning Commission: October 22, 2024 I. — Summary of Proposed Code Amendments: Modified Drainage Regulations 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. — Summary of Proposed LDC Amendments The table below summarizes proposed amendments to Chapter 25-7 (Drainage): Project Type Limitations Drainage Requirements Infill Re-Subdivision [UPDATED] Site Plan Site is no greater than 11,500 square feet Site is over 11,500 square feet, but no greater than one acre Limited to 5-16 dwelling units and site may not exceed 0.50 acres — 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 Projects meeting the “Limitations” described in the second column, above, will not 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. Case No. C20-2023-045 | Page - 3 Case No. C20-2023-045 Planning Commission: October 22, 2024 1. Infill Plats [UPDATED] The staff proposal presented at the Planning Commission’s August 27, 2024, meeting exempted residential re-subdivision applications of no more than a quarter-acre (10,890 square feet) from requirements to provide engineered drainage studies and onsite detention facilities. Based on stakeholder feedback, staff revised its recommendation to increase that threshold to 11,500 square feet. This is double the minimum lot size required for projects seeking to develop two to three-units under Section 25-2-773, which Council amended with passage of the HOME-1 ordinance. So, in addition to providing greater flexibility for re-subdividing into the smaller lot sizes authorized by HOME-2, staff’s revised proposal will facilitate re-subdividing some larger sites into two HOME-1 lots without requiring engineered drainage plans or onsite detention facilities. — Sites No Greater Than 11,500 square feet. Both HOME-1 and HOME-2 focused on the feasibility of adding density to existing single- family lots, either through more units on a single lot or re-subdivision into smaller lots. These proposed amendments will significantly reduce the impact of drainage regulations on projects re-subdividing into smaller lots, 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 almost 80 percent of HOME eligible sites under an acre in size1 to re-subdivide without providing drainage studies or onsite detention facilities. — Sites Greater than 11,500 square feet, But No Greater than One Acre The proposed amendments establish a streamlined drainage review process for sites that are greater than 11,500 square feet 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. 1 An 11,500 square foot site can re-subdivide into six (6) 1,800 square foot lots with additional flexibility to account for the square footage needed for the flagpoles. An 11,500 square foot lot also ensures that the minimum lot area for SF-1 and SF-2/SF-3 (10,000 sf and 5,750 sf, respectively) can be re-subdivided without drainage review. Case No. C20-2023-045 | Page - 4 Case No. C20-2023-045 Planning Commission: October 22, 2024 • No payment would be required under the Regional Storm Management Program (RSMP). If sites 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 a 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 [UPDATED] 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 development, but less density than a large, structured apartment building. As shown in the table on page 6, SF-5 (Urban Family Residence), SF-6 (Townhouse and Condominium Residence), MF-1 (Limited Density), MF-2 (Low Density), and MF-3 (Medium Density) zoning districts allow2 a density of 5-16 units consistent with the goals of Site Plan Lite, Phase 2.3 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 would be unlikely because it would require substantial under-utilization of allowed entitlements. For this reason, as well as concerns regarding the impacts of higher impervious cover associated with larger sites, the staff proposal is capped at half an acre. {intentionally left blank} 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. 3 While it is anticipated that most projects will be on sites zoned SF-6, SF-6, or Multi-Family (MF), commercial sites with a “-MU” combining district and Affordability Unlocked projects in Single-Family (SF) zoning districts would also be eligible to utilize the modified drainage regulations proposed for Site Plan Lite, Phase 2. See Section 25-7-67 (Modified Drainage Standards for Residential Infill). There are approximately 2,500 lots that are under one acre and have the “-MU” combining district. Case No. C20-2023-045 | Page - 5 Case No. C20-2023-045 Planning Commission: October 22, 2024 Allowed Units by Zone and Lot Size Half Acre One Acre Min. Site Area per Unit Type SF-5 & SF-6 Efficiency One-Bedroom 6 Two+ Bedrooms MF-1 MF-2 MF-3 MF-1 MF-2* MF-3* 8 7 6 13 10 9 18 14 12 17 14 12 27 21 18 36 29 24 SF-5 & SF-6 12 Of all lots zoned SF-5, SF-6, MF-1, MF-2, and MF-3, almost 85% are under a half-acre in size and would be eligible for the new modified drainage regulations. An additional 5% of lots are eligible for the modified RSMP regulations proposed for the Drainage Criteria Manual following possible action on this ordinance. See section “Greater than Half an Acre, but No Greater than One Acre” and Appendix A for more specifics. — Half Acre or Less Site plan applications for sites of half-acre or less would be eligible for the same drainage requirements as those outlined above for infill re-subdivisions between quarter-acre and one- 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. 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 half-acre and one-acre may provide an Case No. C20-2023-045 | Page - 6 Case No. C20-2023-045 Planning Commission: October 22, 2024 engineered grading plan to demonstrate runoff to a storm drain system or right-of-way and pay an RSMP payment per Drainage Criteria Manual. 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. II. Modified Impervious Cover Assumptions — 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 the requirement to provide water quality controls. — Effect Tying the assumed impervious cover to the zoning impervious cover will ensure that the maximum number 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 detention requirements, but only three (3) under current assumptions. {intentionally left blank} Case No. C20-2023-045 | Page - 7 Case No. C20-2023-045 Planning Commission: October 22, 2024 III. — Small Project Site Plan 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, many of 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. October 22, 2024: To be considered by the Planning Commission. Council Action: November 7, 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 - 8 ATTACHMENT A Case No. C20-2023-045 Planning Commission: October 22, 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 as well as ongoing efforts of individual departments. 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 is 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:  For infill projects, 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 Case No. C20-2023-045 Planning Commission: October 22, 2024 2. Transportation & Public Works Department (TPW) [UPDATED] 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 without requiring a waiver; 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. These changes include: • For both Site Plan Lite and Infill Plat projects on Level 1 streets, automatically approving requests for relief from right-of-way dedication under LDC 25-6-55 (Dedication of Right-of- Way) without requiring a formal waiver if certain criteria are met. • 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 ATTACHMENT A Case No. C20-2023-045 Planning Commission: October 22, 2024 Parks and Recreation Department (PARD) [NEW] With the goal of increasing efficiency for infill projects, the Parks and Recreation Department (PARD) is establishing a predictable and streamlined process for approving fee-in-lieu of parkland dedication for infill projects meeting certain criteria. The specifics of the process are still in development but are anticipated to be finalized prior to the November 7, 2024, Council meeting. 4. Attachment A (Case No. C20-2023-045) | Page – 3 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 Line 80: Replaced .25 acres with 11,500 square feet PLANNING COMMISSION VERSION THREE WORKING DRAFT-SUBJECT TO CHANGE October 22, 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) (b) (c) does not require a variance from a water quality regulation; does not exceed 5,000 square feet of impervious cover; and 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; 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 THREE WORKING DRAFT-SUBJECT TO CHANGE October 22, 2024 (2) (3) (4) (5) (7) 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; construction of a left turn lane on a divided arterial street; construction of street intersection improvements; (6) widening a public street to provide a deceleration lane if additional right- of-way is not required; 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). Page 2 of 4 COA Law Department PLANNING COMMISSION VERSION THREE WORKING DRAFT-SUBJECT TO CHANGE October 22, 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) (2) The application is a resubdivision that does not exceed a gross site area of 11,500 square feet; or 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. 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 Page 3 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 (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. PLANNING COMMISSION VERSION THREE WORKING DRAFT-SUBJECT TO CHANGE October 22, 2024 (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): (1) (2) (3) (4) (5) (6) 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 for each residential lot not more than 5,750 square feet in size, the amount of impervious cover assumed is; (a) (b) the maximum amount of impervious cover allowed under the applicable zoning district regulations; or for lots in the extraterritorial jurisdiction, 2,500 square feet of impervious cover. Page 4 of 4 COA Law Department