§ 22.82 — Marin County Planning Code

22.82.010 - Purpose of Chapter. ¶

This Chapter provides standards for subdivision design, consistent with the policies of the Marin Countywide Plan and the requirements of the Map Act.

(Ord. No. 3577, 2012)

22.82.020 - Clustering Required in Planned Districts. ¶

Proposed subdivisions within the planned zoning districts should be designed to cluster proposed structures in compliance with Article V and Section 22.08.040 (Agricultural District Development Standards).

(Ord. No. 3577, 2012)

22.82.025 - Density Range. ¶

As a general rule, the residential density established by the zoning for a property shall be used to calculate the maximum number of residential lots potentially resulting from a subdivision. However, the maximum number of residential lots allowed for proposed subdivisions shall be modified based on a calculation of the net lot area of the original lot, except for proposed lots dedicated to affordable housing. In some cases, this means that properties in zoning districts allowing multiple units per lot will have a higher number of potential residential units than the potential number of residential lots allowable based on the net lot area.

Residential densities shall be construed as maximums, but not entitlements.

(Ord. No. 3577, 2012; Ord. No. 3602, § II(exh. A), 2013; Ord. No. 3666, § II(exh. A), 2017; Ord. No. 3819, § I(exh. A), 2024)

22.82.030 - Drainage Facilities.

Subdivision drainage facilities shall be designed and constructed in compliance with Title 24, Sections 24.04.520 (Drainage Facilities) et seq. of the County Code.

(Ord. No. 3577, 2012)

22.82.040 - Energy Conservation. ¶

The design of a subdivision for which a Tentative and Final Map are required by this Article shall provide, to the extent feasible, for future passive or natural heating or cooling opportunities in the subdivisions, in compliance with Map Act Section 66473.1.

(Ord. No. 3577, 2012)

22.82.050 - Hillside Subdivision Design.

Purpose. The provisions of this Section are intended to ensure the creation of suitably designed and developed parcels in all hillside areas of the County.

B.

Applicability. All parcels created within zoning districts which establish minimum lot area requirement, shall be related to the natural ground slope as provided by this Section. This section shall also apply in determining minimum lot size requirements for the purposes of compliance with Chapter 22.92 (Merger of Parcels).

C.

General requirements. Proposed subdivisions shall be designed so that each parcel complies with the minimum lot area requirements of this Chapter, in addition to the minimum lot area requirements of Article II (Zoning Districts and Allowable Land Uses) and Article V established for each zoning district. All parcels created after the effective date of this Development Code shall be related to the natural ground slope as provided by this Section. In the event of conflict between these provisions and applicable minimum lot area standards of Articles II or V, the larger minimum lot area standards shall be required where a minimum lot area applies.

1.

Measurement of slope. The average slope of a lot expressed as a percent is calculated as follows:

S = (L × I × 100)/A

Where:

S =	The average slope of natural ground expressed as a percent
I =	The topographic contour interval in feet (i.e., 2-foot contour intervals, 5-foot intervals, etc.)
L =	The sum of the length of the contour lines expressed in feet
A =	The area of the lot expressed in square feet

This definition assumes that slope calculations are based on accurate topographic survey maps drawn to a scale of not less than one inch equals 100 feet, with contour lines at maximum ten-foot intervals for ground slope over 15 percent, and at five-foot intervals for ground slope of 15 percent or less.

2.

Minimum lot area based on slope. The minimum lot area requirements established by Table 6-1 (Minimum Lot Area Based on Slope) shall apply to all parcels in the unincorporated area of the County, unless any of the lot-slope requirements of Subsection D below (Special Area Lot Size/Slope Requirements) apply. The natural ground slope calculation of a site shall be rounded up to the nearest whole number shown on Table 6-1 (Minimum Area Based on Slope).

Lot design. Unconventional lot design to meet lot-slope requirements shall not be permitted. All lots shall be developable, buildable, and reasonably accessible. Lots shall not be created which are impractical for improvement due to steepness of terrain, location of water courses, inability to handle waste disposal, or other natural or manmade physical conditions.

TABLE 6-1

MINIMUM LOT AREA BASED ON SLOPE

Natural Ground Slope (%)	Minimum Lot Area (sq. ft.)
0—6	See Zoning Map
7	7,667
8	7,849
9	8,086
10	8,376
11	8,719
12	9,117
13	9,572
14	10,088
15	10,670
16	11,324
17	12,053
18	12,865
19	13,763
20	14,752
21	15,836
22	17,016
23	18,293
24	19,667
25	21,136
26	22,693
27	24,331
28	26,041
29	27,808
30	29,616
31	31,446
---	---
32	33,272
33	35,067
34	36,798
35	38,428
36	39,915
37	41,212
38	42,265
39	43,016
40 or greater	43,560

D.

Special area lot size/slope requirements. The following slope-based minimum lot area requirements for new subdivisions apply only in the Community Plan areas and other specific areas noted, instead of the requirements of Subsection C.2 above (Minimum Lot Area Based on Slope):

TABLE 6-2

SPECIAL AREA LOT SIZE/SLOPE REQUIREMENTS

Location	Average Natural Lot Slope	Minimum Lot Area
Sleepy Hollow	15% or less	15,000 sq. ft.
	More than 15%	15,000 sq. ft., plus 1,000 sq. ft. for each additional one percent of slope over 15%, to a maximum of 45,000 sq. ft.
Indian Valley	Less than 10%	1.0 acres
	10% to 20%	1.5 acres
	More than 20%	2.0 acres

(Ord. No. 3577, 2012)

22.82.060 - Roadway Landscaping. ¶

Subdivision landscaping to enhance the natural environment and appearance of the subdivision shall, at a minimum, be designed and constructed in compliance with Title 24, Sections 24.04.750 et seq. (Trees and Landscaping) of the County Code.

(Ord. No. 3577, 2012)

22.82.070 - Lot Configuration and Minimum Area. ¶

Proposed subdivisions shall be designed so that all lots are in compliance with all applicable minimum lot area requirements of this Development Code, except when the project entails subdivision allowed by Government Code Section 51230.2. Lots should be designed with configurations that ensure each property owner can easily understand parcel boundaries, and to respect environmental and topographic conditions of the site. Irregular lot configurations that are designed solely to meet minimum lot area standards based on the lot-slope requirements contained in Section 22.82.050 (Hillside Subdivision Design) shall not be permitted. Lots shall not be approved unless they are developable, buildable, and reasonably accessible. Lots shall not be created which are impractical for improvement, due to steepness of terrain, location of water courses, inability to handle waste disposal, or other natural or manmade physical conditions. In addition to the provisions of this Chapter, lot design shall comply with those standards established by:

A.

Article II (Zoning Districts and Allowable Land Uses);

B.

Article V (Coastal Zones—Development and Resource Management Standards);

The Zoning Maps (Section 22.06.030 (Zoning Map Adopted)); and

D.

Title 24, Chapter 24.07 (Lots) of the County Code.

(Ord. No. 3577, 2012; Ord. No. 3602, § II(exh. A), 2013)

22.82.080 - Roads, Sidewalks, Pathways, Driveways. ¶

Subdivision roadways, sidewalks, pedestrian and multipurpose pathways, and individual driveways shall be designed and constructed in compliance with all applicable provisions of the County Code, including:

A.

Title 24, Sections 24.04.020 et seq. (Roads);

B.

Title 24, Sections 24.04.235 et seq. (Driveways);

C.

Title 24, Sections 24.04.430 et seq. (Sidewalks and Pedestrian Paths); and

D.

Title 24, Sections 24.04.510 (Multipurpose Pathways).

(Ord. No. 3577, 2012)

22.82.090 - Utilities. ¶

Subdivision utilities shall comply with Title 24, Sections 24.04.840 et seq. (Utilities) of the County Code. Utilities to serve proposed development shall be placed underground except where the Director determines that the cost of undergrounding would be so prohibitive as to deny utility service to the development, or the environmental benefit of allowing utilities to be placed above ground out weighs potential visual impacts.

(Ord. No. 3577, 2012)

Chapter 22.84 - TENTATIVE MAPS