Watering schedule
El Cajon Sprinklers: How Often to Water Your Lawn in El Cajon
A schedule built for clay soil and dry summers, inside the rules your water supplier actually sets.
- El Cajon and East County9 nearby communities, all within 20 miles
- Licensed, insured local contractorsWe work with them; check any license at cslb.ca.gov
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El Cajon Sprinklers put this watering guide together for El Cajon and East County homeowners setting a controller for the season. There is no single right number of minutes. There is a right approach for the soil under most of East County, and a set of rules that differ by water supplier, and both are below.
How much water a lawn needs
HomeGuide's rule of thumb is that most lawns need about an inch of water a week, adjusted for weather, soil and the system, and that one or two deep waterings a week are better than frequent shallow ones. In El Cajon, which averages only about 11.6 inches of rain a year, nearly all of it in the cooler months, the system supplies most of that inch for most of the year. August highs around 86 degrees push the need up; a cool, cloudy spring brings it well down.
Why the soil changes the schedule
The USDA soil survey maps central El Cajon as about 13 inches of sandy loam over a dense clay subsoil that takes water at roughly three hundredths of an inch an hour. Water goes into the top layer readily, then stops at the clay. A single long cycle overfills the top layer and runs off. The same inch delivered as two or three short cycles with an hour's soak between them goes in.
On the Diablo clay mapped in Santee, Spring Valley and Lemon Grove, water goes in slowly from the surface down, so cycles need to be shorter still. In Alpine, on about 8 inches of coarse soil over granite, water goes in fast but the soil holds little, so lighter, more frequent watering suits it better than deep soaks.
Water running where it should not? Describe what you see and get a price range on the phone.
Call (619) 361-7869The rules, supplier by supplier
Helix Water District
Serves most of El Cajon, La Mesa, Lemon Grove, Spring Valley, Casa de Oro and Mount Helix. Currently at Level 0, its normal condition: no limit on watering days, times or minutes. Permanent rules: no runoff onto hardscape, streets, structures or neighbors, and no watering for at least 48 hours after rain.
Padre Dam Municipal Water District
Serves Santee, Alpine and parts of El Cajon and Lakeside. Measures in effect at all times: spray heads and hoses limited to 10 minutes per area per day; water only before 10 a.m. or after 6 p.m.; no runoff; no watering during or for 48 hours after rain.
Otay Water District
Serves Rancho San Diego and parts of Spring Valley. Permanent rules: no runoff or overspray onto sidewalks, driveways, roadways or structures, and no irrigation during a storm or for 48 hours after a quarter inch or more of rain at Lindbergh Field.
City of Poway
Irrigate residential landscape between 6 p.m. and 10 a.m. only, with state rules on runoff and rain on top.
Lakeside Water District
Serves most of Lakeside. Check its current rules on the district's site; state rules on runoff and rain apply everywhere.
A starting schedule for clay
- Pick the watering days your supplier allows, and plan on two or three in summer
- Split each lawn zone into two or three short cycles, an hour apart
- Run them before 10 a.m., which satisfies every supplier above
- Watch the first cycle; when water starts to run off, that is the cycle length
- Cut run times back in spring and fall, and turn irrigation off through the rainy months when rain is doing the work
- Skip the 48 hours after rain
A weather-based controller does most of this automatically and earns an $80 SoCal Water$mart rebate on qualifying models; see smart irrigation controller installation.
Rotating nozzles change the minutes
A zone retrofitted with rotating nozzles, at about 0.4 inches an hour against about 1.5 for fixed spray, needs much longer run times to apply the same water. That is the point: slower water soaks in. It also means a schedule copied from a spray zone will underwater a rotating zone. In Padre Dam's area, confirm how the 10-minute limit applies before setting long cycles.
Not sure which of these you are looking at? Most people are not. Call and describe it.
Call (619) 361-7869Through the year in El Cajon
The year here divides roughly in two. From late spring through early fall, warm, dry weather and highs around 86 degrees in August mean the system carries the lawn, and two or three watering days with split cycles is a typical pattern. Through the cooler months, when most of the area's roughly 11.6 inches of rain falls, the lawn needs far less, and in a wet stretch the controller can sit off entirely.
The months in between are where most water is wasted, because a controller set for summer keeps running on a summer schedule into a cool, damp spring. A seasonal adjustment, which most controllers offer as a single percentage, or a weather-based controller that recalculates from local weather each day, takes care of the in-between months without anyone remembering to do it.
Signs the schedule is wrong
- Runoff before a cycle ends (cycles too long)
- A lawn that stays soggy and grows fungus (too frequent)
- Shallow roots and a lawn that wilts by afternoon (too shallow and too frequent)
- Brown areas in a lawn that is otherwise wet (coverage, not schedule)
Watering questions
How often should I water my lawn in El Cajon?
Usually two or three days a week in summer, less in spring and fall, aiming at about an inch a week split into short cycles so the clay can absorb it.
What time can I water in El Cajon?
Helix sets no time limit at Level 0. Padre Dam allows watering before 10 a.m. or after 6 p.m.; Poway between 6 p.m. and 10 a.m. Before 10 a.m. works for all of them.
How long should I run my sprinklers?
Until just before water starts to run off, then stop and repeat after a soak. On clay, that is often only a few minutes per cycle with spray heads.
Can I water after it rains?
Not for 48 hours. Helix, Padre Dam, Otay and state rules all prohibit it.
Is there a limit on watering minutes?
For Padre Dam customers, spray heads and hoses are limited to 10 minutes per area per day. Helix currently sets no limit on minutes.
Tell us which zone is acting up
Say what you are seeing (a geyser, a dry patch, a zone that will not shut off, a timer that went blank) and roughly how big the yard is. You will hear what the fix usually involves and what it tends to cost before anyone comes out.
Call (619) 361-7869