Chapter 8.138 — RM-CZ DISTRICT (RESOURCE MANAGEMENT DISTRICT- COASTAL ZONE

The purposes of this chapter are to carry out the objectives and policies of those San Mateo County General Plan Chapters that fulfill the requirements for State-mandated Open Space and Conservation Elements, as well as other elements adopted as part of the General Plan of San Mateo County, to meet the requirements of Section 65910 of the Government Code of the State of California requiring formulation of an open space zoning ordinance, and to ensure consistency between the General Plan and the zoning ordinance.

(Prior code § 6900 Amd. Ord. 3877: 01/19/99)

The Resource Management-Coastal Zone District (hereinafter the RM-CZ District) shall supplant and replace in name those F-1, A-1, and A-2 Districts that are combined with S-13 and S-11 Districts. The RM-CZ District may also be applied to other areas of the County when they are rezoned to such district.

These regulations shall not apply to a building or structure or portion thereof or use of building or land which does not conform to the zoning regulations and which lawfully existed at the time these regulations, with which it does not conform, became effective.

All parcels 5 acres or larger in size which were legally in existence at the time of the enactment of this ordinance shall continue to be legal parcels. Parcels smaller than 5 acres in size shall continue to be legal parcels only if no adjacent property was in the same ownership at the time of enactment of this ordinance, or if a potable on-site water supply had been developed on the parcel at the time of enactment of this ordinance. When such parcels can be aggregated to a minimum of 5 acres, each 5-acre aggregation shall constitute one legal parcel.

The regulations of this district are included in seven (7) major ordinance elements: (1) Maximum forms of development and type of use, as indicated in Section 8.138.070 (2) Development Review Procedures and Criteria, as indicated in Chapter 8.292; (3) General Review Criteria, as indicated in Section 8.292.030 (4) Supplementary Review Criteria, for Primary Resource Areas, as indicated in Section 8.292.100; (5) Supplementary Review Criteria for Special Hazards Areas as indicated in Section 8.292.180; (6) Primary Resource Areas and Hazard Areas; and (7) the applicable portions of the Zoning District Map, as included in the San Mateo County Zoning Ordinance.

(Prior code § 6902 Amd. Ord. 3877; 01/19/99)

All development proposed for location within an RM-CZ District shall require the issuance of a permit, pursuant to the Development Review Procedure specified in Chapter 8.296, and such proposed development shall comply with the California Environmental Quality Act (CEQA), Section 15020.or purposes of Chapters 8.134, 8.292, 8.296, and 8.138, but excluding those uses defined below, “development” shall mean the construction of any significant structure on land, or in or under water; the discharge or disposal of any significant dredged material or any gaseous, liquid, solid or thermal waste; the division or subdivision of land into two or more parcels; reconstruction or substantial alteration of any significant structure, including any facility of a private, public or quasi-public utility; and any major removal of vegetation.

Excluded from this definition of development and from Development Review Permits and Procedures are uses defined in Section 8.296.090 and commercial logging which is controlled under regulation of the Timber Harvesting Ordinance, Chapters 8.408 off the San Mateo County Ordinance Code; topsoil operations which are subject to regulations of the County Ordinance Code, Chapter 8.412 Topsoil Site Regulations, quarrying operations which are subject to regulation of the County Ordinance Code, Chapter 8.420, Quarries; oil and gas well regulations, Chapter 8.424, and grading and excavating operations which are subject to regulations of the County Ordinance Code, Chapter 10.64, Regulation of Grading and Excavating Operations; agricultural utility poles; single pump houses of less than 800 cubic feet in size, fences under 4 feet in height constructed of single wire or open wood rail, necessary repairs or maintenance of existing structures, agricultural uses which did not require a permit prior to adoption of this ordinance, and crop harvesting and conversion of land for agricultural use, unless said use or land falls within a Primary Wildlife or Primary Natural Vegetative Area, except that vegetation forming a significant part of the viewshed as seen from urban areas or public roads and trails shall be deleted from the definition of Primary Natural Vegetative Areas in consideration of conversion of land for agricultural use.

For purposes of this ordinance, “Significant Structures” shall be defined as a structure for human occupancy or use such as a single-family residence, multiple-family residences, trailer park structures, structures for overnight accommodations, restaurants, churches, private and public club structures, and schools, roads, bridges, public facilities and utilities, nonagricultural utility poles and structures, dams, breakwaters, mineral extraction buildings and constructs, harbors, docking facilities, recreation buildings and facilities, campground structures, dude ranch structures and similar types of structures.

(Prior code § 6903 Amd. Ord. 3877; 01/19/99)

• (a) The Director of Planning shall be responsible for notifying and furnishing information to interested persons and agencies, for coordination, accumulation and presentation of data to the Planning Commission and Board of Supervisors, for making recommendations relating to the overall design, and for assuring compliance with the provisions of this ordinance.

• (b) The County Engineer and Road Commissioner shall be responsible for making recommendations pertaining to public and private roads, all such improvements within road rights of way including but not limited to storm drainage, sewer, water, traffic control, street lighting and public utilities facilities, and for making recommendations in connection with site development, grading erosion control, and matters related to soil

stability and geology of the development. They shall be responsible for the review of reports, final maps and improvement plans required.

• (c) The County Health Officer shall be responsible for: (1) submission of a report stating the recommendations and conditions that must meet the standards and requirements pertaining to water supply, sewage disposal, and other environmental health matters, (2) certification that the quality and quantity of the domestic water supply meets County and State regulations, and (3) final approval of the method of sewage disposal, including consideration of State and local requirements.

• (d) The County fire authorities shall be responsible for making recommendations pertaining to fire prevention and means for protection from fires.

• (e) Officers shall submit their reports to the Director of Planning for submission to the Planning Commission and Board of Supervisors. Each of said officers shall be responsible for making necessary inspections with regard to the matters for which they are responsible to insure compliance with the requirements of this chapter and the conditions of approval.

The following provisions relating to use, density and intensity of development ensure that development is consistent with levels of services which reasonably can be provided, will conserve natural features and scenic values, and that areas hazardous to development or life are left in open or limited use. These provisions are maximum limits and, where applicable, more restrictive requirements imposed by the application of review criteria under Chapter 8.292 shall supersede Sections 8.138.070-8.138.100

The following uses only shall be permitted in the RM-CZ District, except those subject to the provisions of Section 6500 which require a use permit:

• (a) Agricultural uses and accessory structures, temporary roadstands for seasonal sale of produce grown in San Mateo County, providing that 1) sales activities are limited to less than a nine-month operating period per year, 2) all structures are of portable construction and shall be removed from the site within 10 days of the seasonal closure of the stand, 3) roadstand size shall be limited to 200 square feet and appearance, including signs, color and materials, is consistent with the policies of the certified LCP and meets the satisfaction of the Director of Planning and Building; and 4) access and parking requirements meet the satisfaction of the Director of Public Works, however, no impervious paving shall be required.

• (b) Nurseries and greenhouses.

• (c)* Temporary trailer parks and other housing for farm laborers.

• (d) Livestock raising and grazing.

• (e) Dairies.

• (f)[1] Kennels or catteries.

• (g)[2] Timber harvesting and commercial woodlots, providing that no commercial timber harvesting shall occur within 1,000 feet of any legal dwelling in existence on June 18, 1991, except under the following circumstances:

  • (1) Timber harvesting operations for which all permits had been received on or before June 18, 1991, may complete operations in accordance with the terms and conditions of such permits.

  • (2) Timber harvesting operations may occur within the 1,000-foot buffer zone with prior written approval of the owner of the affected dwelling, subject to the prior recordation of the statement specified in Chapter 8.360.

  • (3) Normal forest maintenance may be conducted within the 1,000-foot buffer zone, but shall be limited to: (a) removing dead, dying, or diseased trees and snags; (b) salvaging downed wood; (c) cutting trees for the purposes of developing viewsheds or landscape aesthetics in accordance with other applicable provisions of this Part and of Division VII, San Mateo County Ordinance Code; or (d) clearing for firebreaks, in accordance with requirements of the County Fire Marshal or other applicable fire authority having jurisdiction.

Notwithstanding the above, access roads to the site of timber harvesting operations may be constructed, improved, and used within the 1,000-foot buffer zone. The limitation on harvesting within 1,000 feet of an existing dwelling shall not apply to a dwelling located on the parcel which is proposed for timber harvesting.

For the purpose of this section, the distance from a dwelling shall be measured along the surface of the ground.[a]

• (h)[4] Quarries and waste disposal sites.

• (i) Single-family residences.

• (j) Multi-family residences.

aNot effective in the Coastal Zone unless and until certification without change by the California Coastal Commission. Certification had not occurred as of the reprinting date of this Chapter {July 1999}.

• (k)* Hotels, motels and restaurants.

• (l)* Churches.

• (m)* Schools.

• (n)* Fire stations.

• (o)* Public and private clubs.

• (p) Public recreation.

• (q)* Commercial recreation, including but not limited to stables and riding academies, golf courses, campgrounds, dude ranches, and motorcycle parks in accordance with adopted policies on motorcycle parks and related facilities.

• (r)[3] Oil and gas exploration, production and storage.

• (s) Home occupations.

• (t)* Wineries.

• (u)* Exotic animals for which a use permit has been obtained in accordance with Chapter 6.08 of the San Mateo County Ordinance Code are permitted in addition to those animals otherwise permitted by this chapter.

• (v)* Aquaculture development.

• (w)* Repair, alterations, and additions to existing cemeteries.

• (x)* Scientific/technical research and test facilities, provided a use permit shall only be issued for this use upon the following findings:

  • (1) That the use is of a low-intensity nature with a minimum of permanent construction required, no permanent on-site personnel or permanent on-site vehicles.

  • (2) That the nature of the operation requires an open, isolated, and radio frequency interference-free environment.

  • (3) That no manufacturing or industrial activities are involved.

  • (4) That the size, location and design of any proposed facility as well as level of activity on the site are compatible with the policies of the Local Coastal Plan.

  • (5) That the proposed use does not impair existing or potential agricultural uses on the site or on surrounding properties. The applicant shall demonstrate how agriculture will not be impaired, including provisions for leasing portions of the site for agricultural uses.

  • (6) That the proposed use of facility does not create a potential for any health or safety hazard.

  • (7) That the applicant for such a facility shall describe the manner in which other users might be accommodated in sharing the proposed facility so as to avoid the duplication of such facilities in the future.

• (y)* Corporation/maintenance yards for public purposes.

• (z)* Permanent roadstands for the sale of produce.

• (aa) Keeping of pets in association with a one-family dwelling.

• (ab) Limited keeping of pets in association with a farm labor housing unit or multiple-family dwelling unit.

• (ac) Animal fanciers.

• (ad)* Veterinary hospitals for small animals.

• (ae)* Veterinary hospitals for large animals.

• (af) Keeping of confined animals.

*Uses allowed subject to a use permit

1Allowed subject to a kennel/cattery permit

2Allowed subject to timber harvesting permit 3Allowed subject to oil well permit 4Allowed subject to quarry permit

(Prior code § 6905(a) Amd. Ord. 3263; 09/11/90)

(Prior code § 6905(f)(aa)-(ae) Amd. Ord. 03450 12/15/93)

(Prior code § 6905(g) Amd Ord. 3381; 04/92) - CA Coastal Commission certified Amd. 12/13/00, eff. In Coastal Zone 01/13/01)

(Prior code § 6905(t)&(u) Ord. 2781; 04/06/82)

(Prior code § 6905(w) Ord.2863; 12/13/83)

(Prior code § 6905(w) Amd. Ord.3276; 11/06/90)

(Prior code § 6905(x) Ord. 2872; 01/17/84)

(Prior code § 6905(x) Ord. 3128; 10/06/87)

(Prior code § 6905(x) Amd. Ord.3189; 10/24/89)

(Prior code § 6905(z) Ord. 3189; 10/24/89)

(Prior code § 6905(af) Ord. 4075; 03/20/02)

In the RM-CZ District, for purposes of determining the maximum total number of dwelling units permissible on any parcel, the following system shall be used:

The total parcel shall be compared against the criteria of this section in the order listed. Once considered under a criterion, a segment of the parcel shall not be considered under subsequent criteria. When the applicable criteria have been determined for each of the areas, any portion of the parcel which has not yet been assigned a maximum density accumulation shall be assigned a density of one density credit per 40 acres.

The sum of densities accrued under all applicable categories shall constitute the maximum density of development permissible under this section. If the fractional portion of the number of dwelling credits allowed is equal to or greater than .5, the total number of dwelling credits allowed shall be rounded up to the next whole density credit. If the fraction is less than .5, the fractional unit shall be deleted. All legal parcels shall accumulate at least one density credit.

Expanded or additional non-agricultural uses shall only be permitted on a parcel when there are enough density credits available to that parcel to meet the density credit requirements of this Section for both (a) existing uses, and (b) any

expanded or additional uses, and only where such development meets all other applicable policies of the Local Coastal Program.

Amount of Development Allowed for Non-Agricultural Uses, Except Visitor-Serving, Commercial Recreation and Public Recreation Uses

For new or expanded non-agricultural uses, except visitor-serving, commercial recreation, and public recreation uses, one density credit shall be required for each 315 gallons, or fraction thereof, of average daily water use during the two months of highest water use in a year. This requirement applies to water use by or resulting from the non-agricultural use, including landscaping, swimming pools and all other appurtenant uses.

Residential Uses

For new or expanded residential uses, a single-family dwelling unit shall be deemed to use 315 gallons of water per day during the two months of highest water use in a year (including landscaping, swimming pools and all other appurtenant uses).

Non-Agricultural Uses Except Visitor-Serving Uses

For non-agricultural uses, except visitor-serving uses, the amount of development allowed for each density credit in accordance with the requirements of this policy shall be the amount stated in Table 1.5 in the column headed “Number of Measuring Units Per Density Credit Based on Peak Daily Water Use With Conservation Fixtures.”

Amount of Development Allowed for Visitor-Serving, Commercial Recreation, and Public Recreation Uses

For new or expanded visitor-serving, commercial recreation and public recreation uses, one density credit shall be required for the first 945 gallons, or fraction thereof, of average daily water use during the two months of highest water use in a year. One additional density credit shall be required for each 630 gallons, or fraction thereof, of average daily water use during the two months of highest water use in a year.

This requirement applies to water use by or resulting from the visitor-serving use, including landscaping, swimming pools and all other appurtenant uses. The 945-gallon water use allowance for one density credit may be applied one time only on a parcel.

For visitor-serving, commercial recreation, and public recreation uses listed in Table 1.5, the amount of development allowed for each density credit in accordance with the requirements of this policy shall be:

First Density Credit

For one density credit or the first density credit when multiple density credits are available, either 1 1/2 times the amount stated in Table 1.5 in the column headed “Number of Measuring Units Per Density Credit Based on Peak Daily

Water Use With Conservation Fixtures,” or the amount stated in that column and a residential dwelling unit associated with a visitor-serving facility that is occupied by the facility owner or operator.

Additional Density Credits

For each additional density credit, the amount stated in Table 1.5 in the column headed “Number of Measuring Units Per Density Credit Based on Peak Daily Water Use With Conservation Fixtures.”

For the purpose of this provision, “visitor-serving, commercial recreation, and public recreation uses” shall be only those lands and facilities listed in LCP Policies 11.1, 11.2 and 11.3, and only if those lands and facilities specifically enhance public opportunities for coastal recreation.

As an interim limit, no more than 600 visitor-serving lodging units may be approved in the rural Coastal Zone, as specified by LCP Policy 1.23.

The provisions of this section will not apply to farm labor housing, other structures considered to be accessory to agriculture under the same ownership, a residential dwelling unit associated with a visitor-serving facility that is occupied by the facility owner or operator, or density credits transferred in accordance with the provisions established by the Planned Agricultural District Regulations.

(a) Prime Agricultural Lands

One density credit per 160 acres for that portion of a parcel which is prime agricultural land as defined in Section 6351 (i.e., the number of acres of Prime Agricultural Land divided by 160).

(b) Lands With Landslide Susceptibility

One density credit per 160 acres for that portion of a parcel which lies within any of the three least stable categories (Categories V, VI and L) as shown on the U.S. Geological Survey Map MF 360, “Landslide Susceptibility in San Mateo County” or its current replacement (i.e., the number of acres of land susceptible to landslides divided by 160).

(c) Land With Slope 50% or Greater

One density credit per 160 acres for that portion of a parcel which has a slope 50% or greater (i.e., the number of acres of land with a slope 50% or greater divided by 160).

• (d) Remote Lands

One density credit per 160 acres for that portion of a parcel over 1/2 mile from a public road that was an existing, allweather through public road before the County Local Coastal Program was initially certified in November 1980 (i.e., the number of acres of remote land divided by 160).

(e) Land With Slope 30% but Less Than 50%

One density credit per 80 acres for that portion of a parcel which has a slope 30% but less than 50% (i.e., the number of acres of land with a slope 30%, but less than 50% divided by 80).

(f) Lands Within Rift Zones or Active Faults

One density credit per 80 acres for that portion of a parcel which is located within the rift zone or zone of fractured rock of an active fault as defined by the U.S. Geological Survey and mapped on USGS Map MF 355, “Active faults, probably active faults, and associated fracture zones in San Mateo County,” or its current replacement (i.e., the number of acres of land within rift zones or active faults divided by 80).

(g) Lands Within Flood Hazard Areas

One density credit per 60 acres for that portion of a parcel falling within a 100-year floodplain as most recently defined by the Federal Emergency Management Agency, the U.S. Geological Survey, or the U.S. Army Corps of Engineers (i.e., the number of acres of land within the 100-year floodplain divided by 60).

(h) Land With Slope 15% But Less Than 30%

One density credit per 60 acres for that portion of a parcel with a slope in excess of 15% but less than 30% (i.e., the number of acres of land with a slope 15%, but less than 30% divided by 60).

(i) Land Within Agricultural Preserves or Exclusive Agricultural Districts

One density credit per 60 acres for that portion of a parcel within agricultural preserves or the exclusive Agricultural Districts as defined in the Resource Conservation Area Density Matrix policy on March 25, 1986 (i.e., the number of acres of land within Agricultural Preserves or Exclusive Agricultural Districts divided by 60).

(j) All Other Lands

One density credit per 40 acres for that portion or portions of a parcel not within the above areas (i.e., the number of acres of all other land divided by 40).

If the same portion of a parcel is covered by two or more of the subsections (a) and (j), the density credit for that portion shall be calculated solely on the basis of the subsection which permits the least density credit.

(Prior code § 6906 Amd. Ord. 3189; 10/24/89)

(Prior code § 6906 Amd. Ord. 3716; 06/04/96)

(Prior code § 6906 Amd. Ord. 3799; 11/18/97)

(Prior code § 6906(7) Amd. Ord. 3002; 07/03/84)

Require, after any land divisions, that the applicant grant to the County (and the County to accept) a conservation easement containing a covenant, running with the land in perpetuity, which limits the use of the land covered by the easement to uses consistent with open space (as defined in the California Open Space Lands Act of 1972 on January 1, 1980).

(Prior code § 6906.1 Amd. Ord. 2893; 06/05/84)

(Prior code § 6906.1 Amd. Ord. 3189; 10/24/89)

Where it is demonstrated that a development will further the goals and policies of the Open Space and Conservation Element of the San Mateo County General Plan, increases in the maximum allowable density may be permitted.

• (a) Developments where over 80% of the contiguous and compact parcel area is kept free from alteration (except as required for natural resource management purposes) and held in permanent common open space through appropriate forms of restrictions or public dedication, shall be encouraged by granting a bonus density of up to 10% beyond that permitted by the provisions of Section 6906.

• (b) An additional bonus of up to 10% shall be granted if one or more of the following criteria are also met

  1. Auxiliary transportation modes will be used either to reduce the total land area devoted to structures and paved surfaces or to preserve areas of special open space value.

  2. Building and site design, structural systems and construction methods will be employed which both reduce the land area to be altered from a natural state and preserve the overall natural appearance and scale of the area.

In the RM-CZ District, no residential or commercial structure shall exceed three stories or 36 feet in height except: (1) as allowed by use permit provisions in Section 8.336.030 of the San Mateo County Ordinance Code, and (2) in the Midcoast LCP Update Project Area, as shown on the map that is part of this Chapter, no residential structure shall exceed 28 feet in height. If any portion of a structure is used for residential purposes, the height limit for the entire structure is 28 feet.

(Prior code § 6908A Amd Ord. 4564; 05/24/11 - CA Coastal Commission certified 08/24/12, eff. In Coastal Zone 09/07/12)

In the absence of more restrictive provisions within this ordinance, the minimum yards required in the RM-CZ District shall be as follows:

Front: 50 feet

Side: 20 feet Rear: 20 feet

Main and accessory buildings shall be located at least thirty (30) feet apart.

(Prior code § 6908B Amd Ord. 4564; 05/24/11 - CA Coastal Commission certified 08/24/12, eff. In Coastal Zone 09/07/12)

a. In the Midcoast LCP Update Project Area, as shown on the map that is a part of this Chapter, the maximum building floor area for residential uses shall be established according to the following table, except as provided by subsection b.

More than 11,698 sq. ft. 6,200 sq. ft.

The maximum building floor area shall include the floor area of all stories of all buildings and accessory buildings on a parcel. If any portion of a building is used for residential purposes, the floor area of the entire building is included. Maximum building floor area specifically includes: (1) the floor area of all stories excluding uninhabitable attics as measured from the outside face of all exterior perimeter walls, (2) the area of all decks, porches, balconies or other areas covered by a waterproof roof which extends four (4) or more feet from exterior walls, and (3) the area of all garages and carports.

• b. In addition to the limitations set forth in subsection a., permit 250 sq. ft. bonus building floor area for any parcel whose substandard lots are voluntarily merged in accordance with the provisions of San Mateo County Board of Supervisors’ Resolution No. 068386 (Exhibit “G”) during the “voluntary merger period” described therein.

In the Midcoast LCP Update Project Area, as shown on the map that is a part of this Chapter, the amount of parcel area covered by impervious structures less than eighteen inches (18”) in height is limited to ten percent (10%) parcel size. The runoff equivalent of 10% (parcel size) could be achieved by directing runoff to on-site porous areas or through the use of detention basins. Impervious structures include, but are not limited to, non-porous driveways, decks, patios, walkways, and swimming pools.

An exception to the limit may be granted by the Director of Planning and Building upon finding that off-site project drainage, i.e., runoff, will not exceed that amount equivalent to 10% (parcel size). The applicant shall submit a professionally prepared site plan showing topography, drainage, and calculations which demonstrates this finding can be made. The exception provision applies to:

• (a) Non-residential development, and

• (b) Residential development, only if the Director of Planning and Building determines that the exception is necessary for compliance with site planning and design requirements.

In the Midcoast LCP Update Project Area, as shown on the map that is a part of this Chapter, development related grading, e.g., site preparation, shall not occur between October 15 and April 15 in any given year unless the applicant demonstrates to the satisfaction of the Director of Planning and Building and Building Official that the development site will be effectively contained to prevent erosion and sedimentation, and that such site containment has been established and is ongoing. Site containment shall include, but not be limited to, covering stored equipment and materials, stabilizing site entrances and exposed slopes, containing or reducing runoff, and protecting drain inlets.

(Prior code § 6908C-6908E Ord. 4564; 05/24/11 - CA Coastal Commission certified 08/24/121, eff. In Coastal Zone 09/07/12)