Article 11 — Water Efficient Landscaping

Consistent with Title 23, Division 2, Chapter 2.7 of the California Code of Regulations and section 65595(c) of the California Government Code, the purpose of this article is to encourage water conservation through the use of water efficient landscaping methods. These regulations are deemed to be at least as effective in conserving water as, and supersede the provisions of, the model ordinance adopted by the California Department of Water Resources pursuant to section 65595(a) of the California Government Code. (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16)

A. Installation or Replacement of Landscaping. The provisions of this article shall apply to any project that includes the installation of more than five hundred (500) square feet new irrigated landscape area or the replacement of more than two thousand five hundred (2,500) square feet of irrigated landscape area, and that requires any of the following:

1. Building permit pursuant to Chapter 0.5 of Title 9;

2. Grading permit or site development permit pursuant to Chapter 9 of Title 9;

3. Tentative map or tentative parcel map pursuant to Chapter 1 of Title 10; or

4. Conditional use permit, special use permit, minor use permit, variance, planned development permit, hillside planned development permit, design review, or rezoning pursuant to Chapter 2 of Title 10.

Notwithstanding the foregoing, projects which are entirely irrigated with graywater or rainwater captured on site are subject only to the provisions of Section 10-2.3.1106(C).

Notwithstanding the foregoing, registered state or federal historical sites, ecological restoration projects that do not require a permanent irrigation system, mined-land reclamation projects that do not require a permanent irrigation system, or botanical gardens and arboretums open to the public are not subject to the provisions of this article.

B. Existing Landscaping. The provisions of Section 10-2.3.1110 (Existing Landscaping) shall apply to all existing irrigated landscape areas. The provisions of Section 10-2.3.1106 (Development Standards), Sections 102.3.1108(A) and (B) (Operation and Maintenance), and Section 10-2.3.1110 (Existing Landscaping) shall continue to apply to all existing irrigated landscape areas that were subject to the provisions of this article (pursuant to subsection (A) of this section) at the time of installation or replacement. (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16)

A landscape and irrigation plan shall be included as part of the information required with the application for any of the permits listed in Section 10-2.3.1102. The landscape and irrigation plan shall be drawn to scale of an adequate size as determined by the Community Development Director and shall indicate clearly and with full dimensions the following data where applicable:

A. Exterior boundary lines of the property indicating easements, dimensions, and lot size;

B. All adjacent streets or rights-of-way, including bicycle, equestrian, and hiking trails;

C. Location, size, dimensions, and proposed use of all building and structures (including walls, fences, signs, and shade structures) that are proposed or are existing and intended to remain on the site;

D. Any nearby buildings that will cast a shadow on any irrigated landscape areas;

E. Location of all paths, walkways, decks, and other hardscapes;

F. Boundaries of all proposed irrigated landscape areas;

G. Location, size, species, and (if applicable) variety of all proposed plantings and existing plantings that are intended to remain on the site;

H. Boundaries of each hydrozone and special landscape area, labeled by hydrozone as high, moderate, low, or very low water use. Temporarily irrigated areas of the landscape shall be included in the low water use hydrozone for the water budget calculation;

I. Location, type of mulch and application depth;

• J. Location of recreational areas;

• K. Location of areas permanently and solely dedicated to edible plants;

L. Location of areas irrigated with rainwater captured on site, graywater, and/or recycled water;

M. Identify soil amendments, type, and quantity;

N. Type and surface area of all water features (fountains, ponds, etc.). (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16; §4, Ord. 2239, eff. 7/5/24)

An irrigation plan shall be included as part of the information required as part of the application for any of the permits listed in Section 10-2.3.1102. Notwithstanding the foregoing, an irrigation plan is not required for areas which only require temporary irrigation solely for the plant establishment period. The irrigation plan shall be drawn to scale of an adequate size as determined by the Community Development Director and shall indicate clearly and with full dimensions the following data where applicable:

A. Method of irrigation for all plantings;

B. Location, type, precipitation rate, and spray coverage of all overhead spray irrigation devices. Indicate the boundaries of landscape areas using low-volume irrigation devices, and label each area with the type of irrigation devices used (bubblers, drip emitters, etc.);

C. Boundary and number/label of each irrigation valve circuit;

D. Location of all water meters, manual shut-off valves, automatic control valves, irrigation controllers, main and lateral lines, moisture and rain sensing devices, pressure regulators, and backflow prevention devices;

E. Static water pressure at the point of connection to the public water supply;

F. Flow rate (in gallons per minute), application rate (in inches per hour), and design operating pressure (in pounds per square inch) for each irrigation value circuit;

G. Rain harvesting or catchment technologies and their twenty-four (24) hour retention or infiltration capacity;

H. Location of recycled water, graywater, and/or rainwater discharge piping, system components and area(s) of distribution;

I. A written calculation of the maximum applied water allowance (MAWA), total adjusted hydrozone allowance (TA), and estimated total water use (ETWU), as specified in Section 10-2.3.1107. A completed Water Allowance Worksheet, provided by the Community Development Department, may be substituted for this calculation. (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16; §4, Ord. 2239, eff. 7/5/24)

A soil analysis of the planting areas shall be performed prior to the installation of any plant materials, but only after any grading has been completed. The soils analysis shall be conducted by a qualified laboratory and shall include tests appropriate for the laboratory to make recommendations for soil preparation and/or amendments. Such tests shall include soil texture, infiltration rate, pH, sodium, soluble salts, percent organic matter, and recommendations. The soil analysis report shall be made available, in a timely manner, to the professionals preparing the landscape and irrigation design plans in order to accommodate making any necessary adjustments to the plans. Proof of the soils analysis and a written copy of the laboratory's recommendations shall be submitted as part of the certificate of completion required pursuant to Section 10-2.3.1109. (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16)

All irrigated landscape areas shall comply with the following development standards:

A. Soil Preparation.

1. Prior to the installation of plant materials, all planting areas shall be tilled with compost at a minimum rate of four (4) cubic yards per one thousand (1,000) square feet of planting area to a depth of six (6) inches into the soil, and prepared with appropriate soil amendments as recommended by the soil analysis prepared pursuant to Section 10-2.3.1105. Soils with greater than six percent (6%) organic matter in the top six (6) inches of soil are exempt from this requirement.

2. Natural soil amendments, rather than artificial chemical amendments, should be used whenever possible.

3. Prior to planting, compacted soils shall be transformed to a friable condition. On engineered slopes, only amended planting holes need meet this requirement.

• B. Plant Materials and Ground Cover.

1. Planting areas shall be grouped by hydrozone;

2. All exposed soil surfaces of planting areas other than those planted with turf grass or with creeping or rooting groundcovers shall be covered with a minimum three (3) inch deep layer of mulch. The mulch material shall be a type that will remain in place through wind and rain;

3. Organic mulch made from recycled or post-consumer materials is preferred over inorganic materials or virgin forest product, unless the recycled post-consumer organic products are not locally available;

4. Turf grass shall not be planted on slopes greater than twenty-five percent (25%);

5. Turf grass and high water usage plants are prohibited in street medians.

• C. Irrigation.

1. A landscape water meter is required for irrigated landscape areas greater than five thousand (5,000) square feet in area when associated with a residential use classification, and for irrigated landscape areas greater than one thousand (1,000) square feet in area when associated with any other use;

2. If the water pressure within the irrigation system is below or exceeds the recommended pressure of the irrigation devices, the installation of a pressure regulating device is required to ensure that the dynamic pressure at each irrigation device is within the manufacturer's recommended pressure range for optimal performance;

3. A backflow prevention device shall be provided to protect the water supply from contamination by the irrigation system;

4. A flow sensor that detects high flow conditions created by system damage or malfunction is required for irrigated landscape areas greater than five thousand (5,000) square feet in area when associated with a residential use classification, and for all irrigated landscape areas associated with any other use;

5. Master shut-off valves are required on all irrigation systems;

6. All irrigation devices must meet the requirements set in the American Society of Agricultural and Biological Engineers'/International Code Council's (ASABE/ICC) 802-2014 Landscape Irrigation Sprinkler and Emitter Standard. All overhead spray irrigation devices must have a distribution uniformity low quarter of sixty-fivehundredths (0.65) or higher using the protocol defined in ASABE/ICC 802-2014;

7. Irrigation valve circuits shall be grouped by hydrozone;

8. Overhead spray irrigation devices shall not be located on the same irrigation valve circuit as low-volume irrigation devices;

9. Overhead spray irrigation devices shall not be used in planting areas less than ten (10) feet in length or width, or where the shape of the planting area does not conform to the spray pattern of the overhead spray irrigation device;

10. Overhead spray irrigation devices shall not be used for planting areas within twenty-four (24) inches of a non-permeable surface unless the non-permeable surface drains directly into the planting area being irrigated;

11. Overhead spray irrigation devices with precipitation rates in excess of seventy-five-hundredths (0.75) inches per hour shall not be used on slopes greater than twenty-five percent (25%);

12. Overhead spray irrigation devices located on the same irrigation valve circuit shall have matched precipitation rates;

13. Swing joints or riser protection devices shall be used for all overhead spray irrigation devices and aboveground rigid piping that is located within twelve (12) inches of all turf areas, sidewalks and walkways, roads and driveways, bicycle trails, playgrounds, and other areas which are subject to pedestrian, bicycle or automobile traffic;

14. Irrigation valve circuits which include overhead spray irrigation devices shall be equipped with check valves or anti-drain valves that will retain water in the lateral lines after the irrigation system has completed its watering cycle;

15. All irrigation valve circuits located on slopes greater than ten percent (10%) shall be equipped with check valves or anti-drain valves that will retain water in the lateral lines after the irrigation system has completed its watering cycle;

16. All irrigation systems shall be equipped with a manual shut-off valve at the point of connection to the domestic water supply, a backflow prevention device, an automatic irrigation controller that utilizes either evapotranspiration or soil moisture sensor data to automatically adjust watering schedules, and a rain sensor that suspends irrigation during rain;

17. All irrigation systems shall be designed to prevent water runoff where water flows beyond the irrigated landscape area.

• D. Water Features.

1. Recirculating water systems shall be used for all water features;

2. Water features that incorporate fountains, sprays, or other aerial features shall include a water catchment area sufficient to capture the water emitted from said aerial features for recirculation during windy weather.

E. Graywater Systems. All graywater systems shall conform to the California Plumbing Code (Title 24, Part 5, Chapter 16) and any applicable provisions of the Walnut Creek Municipal Code.

F. Stormwater Management and Rainwater Retention. The Landscape Plan shall conform to the grading design shown on the project grading and drainage plans. Landscape planting and irrigation shall comply with the design guidelines and plant recommendation as published in the applicable edition of the Contra Costa County Clean Water Program Stormwater C.3. Guidebook. (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16)

The estimated total water use (ETWU) of the irrigated landscape area shall not exceed the maximum applied water allowance (MAWA), as calculated using the following formulas. A written copy of the completed formulas in a form approved by the Community Development Director shall be submitted as part of the certificate of compliance required pursuant to Section 10-2.3.1109. Notwithstanding the foregoing, this section does not apply to (a) portions of projects irrigated with graywater or rainwater captured on site; or (b) projects which do not include any water features, do not include any overhead spray irrigation devices other than microspray devices and stream rotor heads, and do not include any planting areas containing turf grasses or high water usage plants totaling more than twenty-five percent (25%) of the irrigated landscape area associated with residential use classifications or ten percent (10%) of the irrigated landscape area associated with all other uses.

A. Maximum Applied Water Allowance (MAWA). The maximum applied water allowance shall be calculated as follows, where MAWA is the maximum applied water allowance (measured in gallons of water per year), LA is the irrigated landscape area including all special landscape areas (measured in square feet), and SLA is the special landscape area (measured in square feet):

MAWA (for residential use classifications) = 28.64 x [(0.55 x LA) + (0.45 x SLA)]

MAWA (for all other uses) = 28.64 x [(0.45 x LA) + (0.55 x SLA)]

In mixed use developments, the total MAWA for the project shall be the sum of the MAWA calculated individually for the portion of the irrigated landscape area associated with residential use classifications and the portion of the irrigated landscape area associated with all other uses.

B. Adjusted Hydrozone Allowance (AHA). The adjusted hydrozone allowance for each unique combination of hydrozone and irrigation device identified in the landscape and irrigation plans shall be calculated as follows, where AHA is the adjusted hydrozone allowance, PF is the plant factor for a particular hydrozone, HA is the hydrozone area of each particular hydrozone (measured in square feet), and IE is the irrigation efficiency of the irrigation devices used for each hydrozone. The plant factor (PF) is eight-tenths (0.8) for high water usage plants and cool-season turf grasses, six-tenths (0.6) for warm-season turf grasses, five-tenths (0.5) for moderate water usage plants, two-tenths (0.2) for low water usage plants, and five-hundredths (0.05) for very low water usage plants. The irrigation efficiency (IE) is nine-tenths (0.9) for subsurface irrigation devices, eighty-five hundredths (0.85) for drip emitters, eight-tenths (0.8) for bubblers, seventy-five hundredths (0.75) for stream rotor heads, seventy-five hundredths (0.75) for microspray devices, and seventy-one hundredths (0.71) for all other overhead spray irrigation devices.

AHA = (PF x HA) / IE

C. Estimated Total Water Use (ETWU). The estimated total water use shall be calculated as follows, where ETWU is the estimated total water use (measured in gallons of water per year), AHAT is the sum of all of the adjusted

hydrozone allowances (AHA) calculated pursuant to subsection (B) of this section, SLA is the special landscape area measured in square feet, and WFA is the total surface water area of all water features measured in square feet:

ETWU = 28.64 x ((AHAT + SLA) + (WFA x 0.8))

(§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16; §4, Ord. 2239, eff. 7/5/24)

A. Irrigation Schedule.

1. Operation of the irrigation system shall be regulated by automatic irrigation controllers;

2. All irrigation schedules shall be developed and managed to utilize the minimum amount of water required to maintain plant health;

3. Overhead spray irrigation devices shall not be used between the hours of 10:00 a.m. and 8:00 p.m.;

4. Where available, the applicant is strongly encouraged to consult with the domestic water purveyor when developing the irrigation schedule;

5. The irrigation schedule shall be submitted in writing as part of the certificate of completion required pursuant to Section 10-2.3.1109.

B. System Maintenance.

1. The irrigation system shall be maintained to ensure water use efficiency. This includes but is not limited to repair or replacement of broken or missing components, the removal of obstructions and blockages to irrigation devices, and the repair or replacement of components resulting in water runoff.

2. All irrigated landscape areas shall be regularly maintained to ensure proper operation of the irrigation system. This includes, but is not limited to, trimming plants that are obstructing irrigation devices, replenishing mulch, and periodically aerating and dethatching turf areas.

C. Landscape Irrigation Audit.

1. A landscape irrigation audit shall be conducted by an EPA WaterSense Certified Irrigation System Auditor upon completion of the landscape installation. Landscape audits shall not be conducted by the person who designed or installed the landscaping.

2. The auditor shall prepare an audit report, in a form approved by the Community Development Director, certifying that the installed landscaping, irrigation system, and irrigation schedule meets the requirements of this article.

3. The audit report shall be submitted in writing as part of the certificate of completion required pursuant to Section 10-2.3.1109. (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16)

To ensure compliance with the provisions of this article, the applicant shall provide written certification as follows:

A. Certificate of Compliance. At the time of submittal of an application for a permit or approval listed in Section 10-2.3.1102, the property owner or applicant shall provide a signed and completed certificate of compliance, in a form approved by the Community Development Director, certifying the compliance of the landscape plan and irrigation plan to the provisions of this article. A written copy of the completed maximum water use formulas required pursuant to Section 10-2.3.1107 shall be submitted with the certificate of compliance. Notwithstanding the foregoing, a written copy of the completed formulas is not required if the landscape plan does not include any turf grasses, plants with a high water usage plant factor (PF), and/or water features.

B. Certificate of Completion. Prior to any of the following actions listed below, the property owner or applicant shall provide a signed and completed certificate of completion, in a form approved by the Community Development Director, certifying the completion of a soil analysis and implementation of its recommendations, the completed installation of the landscaping and irrigation indicated on the landscape plan and the irrigation plan, the proper operation of the irrigation system, and the irrigation schedule's compliance with the provisions of this article. A written copy of the soils analysis report required pursuant to Section 10-2.3.1105 and a written copy of the irrigation schedule and audit report required pursuant to Section 10-2.3.1108 shall be submitted with the certificate of completion. A copy of the signed and completed certificate of completion shall also be provided to the water utility providing service to the property upon which the landscaping is located. The following actions listed below shall only occur upon satisfactory verification of compliance with this article and acceptance of the certificate of completion and associated documents by the Community Development Director:

1. Issuance of a certificate of occupancy for a building permit;

2. Final inspection for a grading permit, when a building permit is not otherwise required for the project;

3. Approval of improvements completed under a site development permit, when a building permit is not otherwise required for the project;

4. Establishment of the use approved by a conditional use permit, special use permit, or minor use permit, when installation of the landscaping was required as a condition of approval, and when a building permit is not otherwise required for the project;

5. Acceptance of improvements pursuant to Article 8 of the Subdivision Ordinance (Chapter 1 of Title 10), when the landscaping was required as part of the improvement plan as a condition of approval for a tentative map or tentative parcel map. (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16; §4, Ord. 2239, eff. 7/5/24)

To prevent water waste resulting from inefficient landscape irrigation, the following provisions apply to all existing irrigated landscape areas, regardless of their size:

A. Water Waste Prevention. No property owner or tenant shall permit runoff from an irrigated landscape area due to excessive irrigation run times, low head drainage, overspray, or other similar conditions where water flows onto an adjacent property, walkways, roadways, parking lots, structures, or other non-permeable surface, unless the non-permeable surface drains directly into the planting area being irrigated.

B. No Prohibition of Low-Water Use Plants. The architectural guidelines of a homeowners' association or a common interest development, which include community apartment projects, condominiums, planned developments, and stock cooperatives, shall not prohibit or include conditions that have the effect of prohibiting the use of low-water use plants as a group.

C. Water Use Efficiency. Property owners and tenants are strongly encouraged to utilize resources and services meant to increase water use efficiency, such as irrigation surveys and landscape water use analyses offered by the water utility providing service to the property upon which the irrigated landscape area is located. (§23, Ord. 2108, eff. 4/7/12; §5, Ord. 2157, eff. 10/6/16)

The City may designate by mutual agreement a water utility to implement some or all of the requirements contained in this article. The City may collaborate with water utilities to define each entity's specific responsibilities relating to this article. (§5, Ord. 2157, eff. 10/6/16)