Marin County Municipal Code Ch. 23.10 Water Efficiency in Landscaping

The purpose of this chapter is to safeguard and protect the water resources of Marin County through establishing minimum criteria for water efficiency in landscape and irrigation design.

(Ord. 3118 § 2 (part), 1992)

This chapter shall apply to all projects for which landscape plans are required by the county as part of a discretionary permit review by the county or for which water service is being issued or activated, except as follows:

1. Landscapes irrigated exclusively with reclaimed water or with private well water;

2. Registered historical sites;

3. Ecological restoration projects that do not require a permanent irrigation system; or

4. Single and multifamily projects with a landscaped area of less than two thousand five hundred square feet.

In addition, sports fields, turf play areas within parks, golf courses, school yards and cemeteries are exempt from planting limitations outlined in Section 23.10.040; however, all other portions of this chapter shall be applicable.

(Ord. 3118 § 2 (part), 1992)

The following definitions apply in reference to this chapter:

1. "Cool season turfgrass" means turfgrass species adapted to growth during cooler periods of the growing season.

2. "High-water-using plants" means annuals, cool season turfgrass and other plants recognized as requiring a substantial and continuous supply of water. High-water-using plants have a plant factor of greater than 0.6. Examples include birch, willow and Scotch moss.

3. "Hydrozone" means a portion of the landscaped area having plants with similar water needs.

4. "Irrigation circuit" means a section of an irrigation system, including pipe and sprinkler heads or emitters, operated by a single remote control valve.

5. "Landscaped area" means the affected planting area within the entire parcel, by new plantings and supporting irrigation, excluding building footprints, paved driveways, parking areas, decks, patios, walkways and undisturbed natural areas. Water features are included in the landscaped area.

6. "Low-water-using plants" means plants recognized as able to withstand extended periods without water, once established. Low-water-using plants have a factor of less than 0.4. Examples include coast live oak, manzanita and oleander.

7. "Moderate-water-using plants" means plants recognized as able to withstand short periods without water once established. Moderate-water-using plants have a factor of greater than or equal to 0.4 but less than or equal to 0.6. Examples include camphor, boxwood and Escallonia.

8. "Plant factor" means a number which represents the approximate portion of reference evapotranspiration used by a particular plant.

9. "Porous mulch" means a material applied to the soil surface for the purpose of reducing evaporation. Examples include shredded bark, compost, straw, animal manure and gravel.

10. "Precipitation rate" means the depth of water deposited within a given area during a specific length of time, usually measured in inches per hour.

11. "Reference evapotranspiration" means a resultant of a standard calculation of the quantity of water transpired by a reference crop, usually grass, and evaporated from adjacent soil surfaces.

12. "Runoff" means water which is not absorbed by the soil and "runs off" onto adjacent areas.

13. "Scarify" means to rip, rototill or otherwise break the soil surface.

14. "Water features" means ornamental or functional fountains, pools, ponds, etc., including swimming pools.

(Ord. 3118 § 2 (part), 1992)

Plants selected for landscapes shall be compatible with the climate, geology and topographic conditions of the site. Plants with similar water requirements shall be grouped together in distinct and separate hydrozones. High-water-using plants, such as cool season turfgrass, are permitted when limited in areas such that either:

1. They do not comprise more than twenty-five percent of the landscaped area; or

2. The average plant factor for the entire landscaped area does not exceed 0.5, when calculated using the following estimates or other documented plant factor determinations:

a. The plant factor for cool season turfgrass and high-water-using plants is 0.8,

b. The plant factor for moderate-water-using plants is 0.5, and

c. The plant factor for low-water-using plants is 0.2.

(Ord. 3118 § 2 (part), 1992)

Landscaped areas shall be water conserving and shall be irrigated with an automatic irrigation system which shall be designed to provide efficient irrigation coverage without overspray onto nonlandscaped areas. Automatic irrigation systems shall include:

1. Irrigation controller(s) with repeat start time and multiple-program potential;

2. Automatic rain shutoff device for each controller;

3. Pressure regulation device(s) as required to effect appropriate operating pressures for each type of sprinkler or other application device;

4. Check valves where elevation differential may cause low head drainage;

5. High flow shutoff valves for each overhead sprinkler;

6. Precipitation rates matched within twenty percent of each overhead irrigation circuit;

7. Point application (drip, bubbler) where overhead irrigation will result in overspray, runoff or nonuniform application; and

8. Separate irrigation circuits for different hydrozones, irrigation methods, precipitation rates, solar exposures, microclimates, slopes and soil types.

(Ord. 3118 § 2 (part), 1992)

Soil conditioning shall be suitable to provide healthy growing conditions for plants and to encourage water infiltration and penetration. Soil preparation shall include:

1. Scarifying soil to a minimum depth of six inches; and

2. Amending soil with organic material at a minimum rate of five cubic yards per one thousand square feet or per specific recommendations from a soils laboratory report.

In addition, a minimum two-inch layer of porous mulch shall be applied to exposed soil surfaces of nonturf areas within the landscaped area.

(Ord. 3118 § 2 (part), 1992)

Water features shall be designed to minimize evaporation and shall be as water-efficient as possible. All water features shall use recirculating water. Fountains which spray water into the air are discouraged. The surface area of water features shall be calculated as high-water-using plants (plant factor greater than 0.6) for limitations outlined in Section 23.10.040.

(Ord. 3118 § 2 (part), 1992)

If this chapter is applicable, the following information shall be submitted to the county at the time of application for a development permit:

1. A planting plan which clearly indicates:

a. Location of existing and proposed trees, shrubs, groundcovers, turf and other plants,

b. Listing of proposed plants by botanical and common name,

c. Property lines, building footprints, driveways, parking areas and other hardscape features, undisturbed natural areas and water features,

d. Notes or specifications regarding recommended soil preparation, and

e. Calculations for the square footage limitation or average plant factor determination as outlined in Section 23.10.040;

2. An irrigation plan which clearly indicates:

a. Location of connection to domestic system, including meter size,

b. Location of major irrigation system components, including of controllers, backflow prevention devices, pressure regulating devices, gate valves, automatic control valves, mainline and lateral pipe, rain shutoff devices, sprinklers, etc.,

c. Listing of major irrigation components, including manufacturer, model number and size, where appropriate, and

d. Total flow and precipitation rate for each overhead irrigation circuit;

3. A statement of conformance, signed by a certified or licensed landscape design professional, which confirms that design requirements of this chapter have been met. The statement of conformance form may be obtained from the planning department. As used in this section, "landscape design professional" includes, but is not limited to, landscape architect, landscape contractor, irrigation designer, or golf course architect.

Once installation of the landscape has been completed, a statement of completion, signed by a certified or licensed landscape design professional, shall be submitted to the county which confirms that the landscape was installed as designed. The statement of completion form may be obtained from the planning department.

For projects within jurisdictions of local water districts where landscape water efficiency is required by the water district as a condition of water service, letters from the district confirming project compliance with the district's landscape water efficiency regulations may be accepted in lieu of the requirements listed in this section. These in-lieu letters will be accepted if, in the judgment of the planning director, the district's regulations meet the requirements of this section.

For projects within jurisdictions of local water districts where adherence to landscape water efficiency guidelines is voluntary and a project sponsor agrees to install a landscape in accordance with the district's guidelines which, in the opinion of the district, would be equal to or more water efficient than a landscape installed pursuant to this section, letters from the district confirming the project compliance with the district's guidelines may be accepted in lieu of the requirements listed in this section. These in-lieu letters will be accepted if, in the judgment of the planning director, the district's guidelines meet the requirements of this section.

(Ord. 3118 § 2 (part), 1992)

Any person aggrieved by a determination, interpretation, decision, conclusion, decree, judgment or similar action relative to this chapter may appeal such action as provided in Chapter 22.89 of the Marin County Code.

(Ord. 3118 § 2 (part), 1992)