Surprise Watering Schedule by Season
The City of Surprise publishes watering intervals and depths for every plant type and season. See how to read the table and turn it into a controller program.
Irrigation Guides5 min read
The City of Surprise publishes landscape watering guidelines that set a range of days between waterings for each plant type across four seasons, plus a target depth for each. They are guidance for established plants, not a mandatory schedule. Use them to group stations by plant type, then check soil moisture and plant condition as the seasons change.
Where the guideline comes from
The Landscape Watering Guidelines page sits in the city's water conservation section. It opens with a few design rules before the numbers:
- Sprinklers should serve only turf and should not spray buildings, fences or non-landscaped areas.
- Water before sunrise to cut evaporation.
- Water turf, planters, trees and shrubs separately, because their needs differ.
- Always wet the entire depth and width of the root zone, whatever the time of year.
- Once or twice a year, water twice as long to leach out salts that build up in the soil.
Those rules shape the controller before any interval is chosen. If one valve feeds both lawn spray heads and shrub drip, no schedule from the table can suit both.
How the table is organized
The table lists ten plant groups and four seasons: March to May, May to October, October to December, and December to March. For each pairing it gives a range of days between waterings. The final column gives how deeply to water.
A few rows show the pattern. Desert-adapted trees run from 14 to 30 days between waterings in spring and fall, tighten to 7 to 21 days from May to October, and stretch to 30 to 60 days in winter. High-water-use shrubs need water far more often, every 5 to 7 days in summer. Cacti and succulents go 14 to 30 days in summer and are watered in winter only if needed. Warm-season grass ranges from every 3 to 6 days in summer to every 15 to 30 days in winter. Cool-season grass gets no water in the May to October column.
The depth column is the part people skip:
- Trees: 24 to 36 inches.
- Shrubs: 18 to 24 inches.
- Groundcovers, vines, cacti, succulents and annuals: 8 to 12 inches.
- Warm- and cool-season grass: 6 to 10 inches.
What the notes under the table change
Three notes on the city page matter. The intervals apply to established plants, which the city defines as one year in the ground for shrubs and three years for trees. New plantings and unusually hot or dry weather need more water, and cool or rainy weather needs less. And drip run times are typically two hours or more for each watering.
That last note surprises people who set drip stations for ten minutes a day. A short daily cycle wets the surface and leaves the depth targets above unmet. The table describes infrequent, deep watering, which matches University of Arizona Cooperative Extension advice that light, frequent irrigation builds shallow roots while deep, less frequent irrigation builds stronger ones.
Turning the table into a program
Start with the zone map, not the controller. For each station, write down which plant group it serves. Then set the interval from the current season's column and set the runtime to reach the depth target.
To check depth, Extension suggests pushing a soil probe, a long screwdriver or a piece of rebar into the soil after a cycle. It slides easily through moist soil and stops at dry soil. If a tree station stops at 10 inches, it is not reaching the 24 to 36 inch target, and the answer is a longer run, not an extra day.
Two local factors can throw this off. Caliche, a cemented calcium carbonate layer common in southern Arizona soils, can stop water from soaking down, as the caliche and drainage guide explains. And the city's drinking water is groundwater, so the salt-leaching note is worth following once or twice a year.
Four times a year, at least
The Arizona Municipal Water Users Association recommends adjusting irrigation schedules at least four times a year. The Surprise table's four columns line up with that: a change around March, around May, around October and around December. A seasonal visit is a good time to check heads, drip lines and valves at the same time, because the city's water conservation code lists poorly maintained timers among the causes of water waste.
The city also offers help. Master Gardeners, a free service run with University of Arizona Cooperative Extension, hold office hours on Saturdays from 9 a.m. to noon at the Water Education Center next to the Xeriscape Demonstration Garden, and the water conservation page lists workshops on irrigation efficiency and on irrigation maintenance and repair.
Next step in Surprise
If your stations mix plant types, or the controller has not changed since spring, a seasonal irrigation tune-up in Surprise can match the program to the city guidelines. The seasonal irrigation tune-up page explains what is checked, and the Surprise service area page and all irrigation services list related work. Related reading: Watering New Desert Plants in Surprise and Monsoon Settings for Your Irrigation Controller. For the cold months and overseeded lawns, see winter watering, frost and overseeding in Surprise.
FAQ
Is the Surprise watering table a mandatory schedule?
- No. The city publishes it as landscape watering guidelines for established plants. It notes that new plantings and unusually hot or dry weather need more water, and cool or rainy weather needs less. Use it to set a starting program, then adjust from soil moisture and plant condition.
How deep should I water trees and shrubs in Surprise?
- The city guideline gives 24 to 36 inches for trees, 18 to 24 inches for shrubs, 8 to 12 inches for groundcovers, cacti, succulents and annuals, and 6 to 10 inches for grass. Check depth after a cycle with a soil probe or long screwdriver pushed into the soil.
How long should a drip zone run in Surprise?
- The city's guidelines say drip run times are typically two hours or more for each watering, with days between waterings set by plant type and season. Short daily drip cycles rarely reach the depth targets. Confirm by probing the soil near the plants after a full cycle.
Why does the city say to water twice as long sometimes?
- The guidelines recommend watering twice as long once or twice a year to leach out salts that build up in local soils. A longer, deeper cycle pushes salts below the root zone. Caliche can block that drainage, so check that water soaks in rather than pooling.
When should I change my controller during the year?
- The table's four seasons, March to May, May to October, October to December and December to March, give natural points to adjust. AMWUA recommends changing schedules at least four times a year. Check heads and drip lines at each change as well as the intervals.
Is 20 minutes of watering enough in Surprise?
- For drip, usually not. The city says drip run times are typically two hours or more per watering. For a spray lawn it depends on the nozzles; the city target is wetting grass roots 6 to 10 inches deep. Push a probe in after a cycle to see how far the water reached.
Sources
- Landscape Watering Guidelines surpriseaz.gov
- University of Arizona Cooperative Extension extension.arizona.edu
- Arizona Municipal Water Users Association amwua.org