Irrigation Zone Addition and Expansion in Glendale, Arizona

Adding a zone in Glendale usually follows a change in the yard: a lawn turned into desert planting, a new citrus tree, a bed along a new wall, or a downtown lot that has given up flood irrigation. The local question is whether the water supply can carry another station at the hour it will run.

Measure at the scheduled hour

The City of Glendale is divided into four pressure zones, and the city says pressure may drop from 6 to 8 a.m. and from 6 to 9 p.m. A new station that tests fine at noon may starve at dawn. Run an existing zone at the time the new one will run and watch the far heads. If it is already weak, adding heads to it will make it worse. Splitting it, or putting the new planting on its own drip valve, usually works better. Start times before 6 a.m. also help.

Group the new planting by what it needs

AMWUA says new plants need water every one to two days in summer at first, and every three to four days from fall to spring, until they establish. That takes about a year for shrubs and three for trees. A new bed should not share a valve with established plants, or one group will be drowned to keep the other alive. Typical Glendale groupings:

planting	usual delivery	why it gets its own station
remaining turf	spray or rotor	frequent, shallow cycles
established desert shrubs	drip	deep, infrequent cycles
new shrubs and trees	drip	short-term establishment schedule
citrus	drip ring or bubblers	wide, deep wetting to the canopy edge

University of Arizona's citrus guidance calls for wetting from the trunk to just beyond the drip line, at least two feet deep, which a shrub emitter will not do.

Converting from flood or lawn

On downtown lots that drop the city's urban flood irrigation, mature trees lose a deep basin watering every two weeks in season. A replacement drip zone for those trees has to be sized for their size, not the size they were decades ago. In ranch-house neighbourhoods, a lawn converted to xeriscape may qualify for the city's landscape conversion rebate. The terms include 500 square feet minimum at an existing home, most plants from Arizona's low-water list, a drought-tolerant tree, and HOA compliance. Plan the new zone to suit that layout.

Wiring and the controller

Check that the controller has a spare station before planning. If not, the choice is an expansion module or a new controller. Label the new wire at both ends, add the station to the written zone map, and note the establishment run time so it can be shortened once the plants settle in. A WaterSense smart controller can qualify for the city's irrigation rebate if the old one is not WaterSense listed and the system is otherwise in good working order.

The zone expansion service page covers the work. See the citrus watering guide, drip versus spray and drip irrigation in Glendale.