Tune Up Your Sprinkler System and Stop Watering the Sidewalk
The average system wastes a third of what it sprays through sunken heads, wrong nozzles, and a controller nobody has touched since install. Two hours and $40 fixes most of it.
An irrigation system runs unsupervised at 5 a.m. and never complains. That is exactly why heads sink below the turf, get knocked crooked by the mower, and spend a summer painting the driveway. A tune-up is really an audit: watch every zone run, fix what you see, then reset the controller using real numbers instead of the installer’s guess.
Why the schedule is the last thing you touch
People start with the controller because it has buttons. But you can’t program around a head spraying half its water onto the fence. Fix the hardware, measure what the system actually puts down, and only then set run times. Do it the other way and you’ll spend the season chasing brown spots that were never a schedule problem.
Walk every zone with the water on
Run each zone manually for three minutes while you walk it. Look for heads that don’t pop up, heads hitting pavement, mist blowing sideways (high pressure), water bubbling around a body (a blown seal), and dry arcs. Every head should throw far enough to reach the next head; when that overlap breaks, you get stripes.
Raise, straighten, and clear the heads
A head buried under a half inch of thatch waters grass blades and nothing else. Cut a plug around it, lift the body flush with the soil, and pack topsoil underneath. Reset leaning heads plumb; a tilted head throws long one way and short the other. Pull the nozzle and filter on anything sputtering, rinse the grit, and flush the line for thirty seconds before reassembling.
Adjust arcs and match the nozzles
Set each arc so water lands on the lawn edge, not past it. Then look at the zone as a set: a quarter-circle head should put out a quarter of what a full-circle head does. Mixing rotors and sprays on one zone is the classic mistake — sprays deliver two to three times more water per minute. Swap odd nozzles for matching ones; they cost a few dollars each.
Run the catch-cup test
Space six to eight identical cans across a zone and run it 15 minutes. Measure each depth, average them, and multiply by four for inches per hour. That’s your real rate, usually nowhere near the design number. Any can under half the average marks a coverage gap. Test sprays, rotors, and beds separately; they behave differently.
Set the controller with real numbers
Lawns want about an inch a week in mild weather, delivered in two or three deep soaks. A spray zone measuring 1.5 inches per hour needs 20 minutes twice a week; a rotor zone at 0.5 inches per hour needs an hour. Program that as 100 percent, then use the seasonal adjust: 60 to 70 percent in spring and fall, up to 120 in peak heat, off after real rain. Split any long run on a slope into two cycles an hour apart so water soaks in instead of running off.
If a whole zone is weak or won’t shut off, the problem is at the valve box, not the heads; a humming or weeping valve usually needs a new diaphragm, which is a cheap fix. But leave the backflow preventer to a licensed irrigator. Many towns require an annual certified test, and a failed device can pull fertilizer into your drinking water.
Fix the hardware first, measure what it puts down, and only then set the clock.
Keep it running through the seasons
Repeat the three-minute walk monthly; a mower can knock a head crooked any Saturday. In freezing climates, blow the lines out at no more than 50 psi each fall. Photograph the controller settings before shutdown. And whenever you find a dry spot, resist adding minutes — go look at the head first.
Keep the momentum going
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