A. Pressure Regulation. A pressure regulating valve shall be installed by the builder or developer, and maintained by the owner, if the static service pressure exceeds 90 pounds per square inch (psi). The pressure-regulating valve shall be located between the meter and the first point of water use, or first point of division in the pipe, and shall be set at the manufacturer’s recommended pressure for the sprinklers.
B. Irrigation Controller. It is required that landscaped areas use a Water Sense labeled smart irrigation controller, which automatically adjusts the frequency and/or duration of irrigation events in response to changing weather conditions. All controllers shall be equipped with automatic rain delay or rain shut-off capabilities and shall have memory retention capability to retain pre-programmed irrigation schedules. Sites are not exempt from water waste prohibitions.
C. Each valve shall irrigate a landscape with a similar site, slope and soil conditions, and plant materials with similar watering needs. Grass, trees and non-grass areas shall be irrigated on separate valves. Drip emitters and sprinklers shall be placed on separate valves.
D. Low-volume irrigation equipment (i.e., drip emitters discharging 20 gallons per hour, or less) shall be provided for each tree.
E. Drip irrigation shall be used to irrigate plants in non-grass areas. Spray head to drip conversion for rehabilitated landscape sites may be acceptable with city approval of Irrigation Plans.
F. High conservation efficiency spray nozzles are required for sprinkler applications.
G. Sprinkler heads shall have matched precipitation rates with each control valve circuit.
H. Sprinkler heads shall be attached to rigid lateral lines with flexible material (swing joints) to reduce potential for breakage.
I. Check valves are required. Pressure compensating valves and sprinklers are required where a significant variation in water pressure occurs within the irrigation system due to elevation differences.
J. Filters, pressure regulating valves and end-flush Fittings shall be provided for drip irrigation lines. Drip systems shall not use emitters that discharge more than 20 gallons per hour (GPH).
K. Landscape watering with potable (treated) water is prohibited from 10:00 a.m. to 6:00 p.m., June 1 to September 1, to maximize irrigation efficiency; and it should be limited to the hours of 6:00 p.m. to 10:00 a.m. during times of low wind, year-round, to avoid excessive loss of water through evapotranspiration, with treated or untreated (secondary) water. (c.f., Section 8-6-6)
L. Water waste is prohibited.
1. Waste includes overwatering, irrigating during a precipitation event, water that sprays or flows off your property, failure to comply with drought restrictions and/or a failure to repair irrigation system leaks and/or malfunctions in a timely manner. [See Section 8-1-17.]
2. Overwatering can be avoided by following the Washington County Conservancy District recommended irrigation schedule and practices as noted on wcwcd.org. The generally recommended schedule is:
a. Winter (Nov - Feb) - sprinkler and drip irrigation up to 1 day a week. Irrigation is typically not needed in December and January
b. Spring (Mar - April) - sprinkler irrigation up to 3 days a week and drip irrigation up to 2 days a week
c. Summer (May - Aug) - sprinkler irrigation up to 4 days a week and drip irrigation up to 3 days a week
d. Fall (Sept - Oct) - sprinkler irrigation up to 3 days a week and drip irrigation up to 2 days a week
M. Program valves for multiple repeat cycles are required to reduce runoff on slopes and for soils with slow infiltration rates. (Ord. 2022-08, 9-7-2022; amd. Ord. 2023-14, 12-6-2023)