Almost every irrigation system we get called out to has the same two problems. Neither is exotic, both are fixable without ripping the system out, and together they account for most of what a yard wastes. If your water bill has crept up and nothing looks obviously broken, this is usually where it went.
The first is spacing. Sprinkler heads are designed to be laid out so that the spray from each head reaches the next one — head-to-head coverage. That sounds like overkill and it is not: a sprinkler puts down far more water close to the head than at the edge of its arc, so without that overlap you get a dry ring between every pair of heads. What happens next is the expensive part. The dry rings show, so somebody runs the zones longer to fix them, which does nothing for the rings and drowns everything near the heads. The system was never going to cover evenly; running it longer only wastes more.
The second is zoning. A lawn, a bed of established shrubs, and a row of pots want completely different amounts of water on completely different schedules. Put them on one valve and you have to run it for whichever needs the most — so the lawn gets what it needs and the shrubs get several times too much, year after year. Overwatered shrubs do not look overwatered, incidentally. They look like they are struggling, which usually gets them more water.
Splitting those onto separate zones is the single highest-value change most systems can have made to them. Beds and hedges should generally not be on spray at all — they want drip, which puts water at the root zone with almost nothing lost to evaporation or overspray, and which does not throw water onto walls, fences and the sidewalk on the way past.
While we are on overspray: watering pavement is pure loss, and it is extremely common. Heads that were set correctly get knocked by mowers, settle out of level, or end up with their arc adjusted by somebody guessing. Run each zone and watch where the water actually lands. Anything hitting concrete, a wall or the street is money leaving.
There are two more faults worth checking while a zone is running. Look for a head that mists rather than throws proper droplets — that is pressure too high, and misted water largely evaporates before it lands. And look for a head that keeps dribbling after the zone shuts off, which usually means low-head drainage: the whole line emptying itself out through the lowest head every single cycle.
The controller matters too, and this is the easiest thing to get wrong. A schedule set in March is wrong by July and wrong again by November. Each zone should have its own run time, and the whole thing should be seasonally adjusted — a smart controller does that on its own, but a plain one does the job perfectly well if somebody actually changes it a few times a year. On heavy or sloped ground, splitting a long run into two shorter cycles with a gap between them lets water soak in instead of running off down the driveway.
None of this requires replacing a system. Rezoning, converting beds to drip, correcting spacing, and setting the controller properly will fix the great majority of what we see, and the cost usually comes back off the water bill. Where a system is genuinely past saving we will say so — but we are not going to sell you a new one to avoid a repair.
Millan's landscaping installs, rezones and repairs irrigation across Los Angeles County. Call (323) 697-8198 for a free on-site estimate — we will run your zones with you watching.