Irrigation Blowout & Winterization
The autumn work that prevents most of what this page repairs.
Learn moreIrrigation
Spring Startup Is Where Winter Sends the Invoice
Most irrigation repairs are discovered in the first ten minutes of the season, when the system is charged and the damage from five months of cold reveals itself all at once. Charging it slowly is how you keep that discovery small.
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(833) 472-2088
Startup gone wrong? Tell us which zones and what you're seeing.
Startup done slowly
Charging a cold system at full pressure turns cracks into excavations.
Zone by zone
Each zone run and watched. Problems are local, not system-wide.
Plumbing, not district
We work on your side of the point of delivery, and we'll say where that is.
Repair before it grows
A weeping fitting in May is a soaked lawn and a high bill by July.
Spring
Turning the water back on is a procedure, not a lever
The single most damaging thing done to Idaho irrigation systems each year is charging them quickly. A system that has been empty since October is full of air. Opening the supply valve fast sends a pressure wave through that air and into every fitting, valve body and head on the property, and anything that winter weakened fails at that moment, often more spectacularly than it would have failed on its own.
Startup is done by opening the supply valve slowly, over minutes rather than seconds, so the system fills and the air is displaced gradually. Zones are then run one at a time, in order, with someone watching the lawn rather than the controller. That is when the season's problem list gets written: heads that do not pop, heads that do not shut off, zones with obviously low pressure, water surfacing above a valve box, and any patch of ground that is wet before the sprinklers have reached it.
The backflow assembly is checked first and separately, because it is above ground, it took the worst of the cold, and a failed assembly will make a dramatic mess the moment supply arrives. If it has split, the system does not get charged until it is dealt with, see backflow device repair.
The wet patch that appears before the sprinklers run
Ground that is soft and green while the system is idle means a mainline leak, the section that stays pressurised whenever the supply is open. That one does not wait for a scheduled repair, because it runs continuously and it is metered.
Wet patch that never dries is a mainline leak. That one's urgent.
Symptoms
What the system is doing, and what it means
A zone that will not shut off
Usually a zone valve holding open: debris under the diaphragm, a torn diaphragm, or a solenoid that has failed. Occasionally it is the controller sending continuous power. If the water will not stop, the isolation valve on the manifold is the immediate answer while a repair is arranged.
A zone that will not come on
Electrical as often as mechanical, a broken wire at the valve, a corroded splice in the box, a failed solenoid, or a controller output that has died. Wire faults are common in the valley because splices sitting in a wet box for fifteen years eventually corrode through.
Low pressure across one zone
A lateral leak underground, a partly closed isolation valve, too many heads added to a zone at some point in the past, or a clogged filter. If the pressure loss is new and the ground is wet, look for the leak first.
Low pressure everywhere
Mainline problem, a failing pressure regulator, a partially failed backflow assembly, or a supply-side issue at the point of delivery, which may not be yours to fix.
Heads that weep, mist or flood
Weeping after shutdown is usually low-head drainage: the lowest heads on a slope draining the lateral each cycle, solved with check valves in the heads. Misting means pressure is too high for the nozzles. Flooding at the base of a head is a cracked body or a broken riser, and those are freeze casualties.
The hardware
Everything expensive lives in the valve box
The manifold is where the mainline splits into zones, and it is where most of a system's serviceable parts are concentrated: isolation valves, zone valves with their solenoids and diaphragms, wiring splices and unions. It is also, usually, a plastic box sunk in the ground that has been full of soil, water and spiders since it was installed.
Zone valve repair is often a rebuild rather than a replacement, a new diaphragm and a clean seat solve a large proportion of faults, and it is a fraction of the cost of replacing the valve. Replacement makes sense when the body itself is cracked from freezing, when the valve is old enough that parts are awkward, or when several in the same manifold are failing together, which usually means they are all the same age.
Manifold plumbing itself fails at the fittings. Freeze damage cracks the plastic; ground movement and root pressure stress the joints; and manifolds assembled with the wrong solvent or in cold weather come apart years later. Rebuilding a manifold properly, with unions so that future valve work does not require cutting pipe, is one of those repairs that pays for itself the second time something needs attention.
Wiring deserves attention at the same time. Splices should be in waterproof connectors, not tape, and a common fault is a valve that works intermittently because a corroded splice makes contact only when the box is dry.
Spring is the busiest irrigation window. Book early in the week.
Excavation work
Finding a buried lateral leak without digging up the lawn
Underground leaks are the repairs people dread, and the dread is mostly about excavation rather than plumbing. Locating precisely is what keeps the hole small.
The evidence usually comes first: a soft, spongy or unusually green area; water surfacing when a particular zone runs; a zone that has lost pressure; a sinkhole or depression along a trench line; or gravel and soil washing out onto a path. Where the leak is on the mainline rather than a lateral, the wet area persists between waterings, which is the clearest single diagnostic on the whole page.
Narrowing it down is done by zone isolation, running each zone in turn and watching where water appears, then closing zones to see whether the wet area persists. Where the surface evidence is ambiguous, pressure testing an isolated section identifies which run is losing water before anyone puts a shovel in the ground.
The repair itself is straightforward: expose the damaged section, cut back to sound pipe, install a coupling or a new length, pressure-test the zone, and backfill properly so the ground does not settle into a trench-shaped dip over the summer. Where a lateral has failed in several places, replacing the run is often cheaper than three separate excavations.
One caution particular to this state: irrigation piping frequently shares a trench, or a route, with other buried services. Locating utilities before digging is not optional, and any contractor who skips that step is one to avoid.
Boundaries
Your system, the district's system, and the line between
Pressurized irrigation in the Treasure Valley is delivered by irrigation districts and municipal providers, and there is a defined point where their responsibility ends and yours begins. Knowing which side a problem sits on saves a great deal of time and money.
Generally the provider's side: the delivery main in the street, the connection to it, the point-of-delivery valve, and the schedule on which water is turned on and off each season. If the whole neighbourhood has no pressure, that is not a repair you should be paying for.
Generally yours: everything downstream of the point of delivery, the backflow assembly, the mainline across your property, the manifold, zone valves, laterals, heads, wiring and controller. That is the work we do.
Not us, at all: backflow certification testing, which is a separate service with requirements that differ by district and city; anything requiring work on the district's own infrastructure; and irrigation district billing or scheduling questions, which belong to your provider.
We will tell you plainly when a problem sits on the other side of that line, including when the honest answer is that your system is fine and the water simply is not being delivered yet. Every year, a number of "my sprinklers are broken" calls in April turn out to be a district that has not turned the water on.
Zone stuck on? Close the isolation valve, then call.
How it runs
A repair visit, in order
Diagnosis is mostly observation, running the system and watching the ground.
Charge slowly, watch closely
Backflow assembly checked first, then the supply opened gradually and each zone run in turn while the ground and the heads are watched.
Isolate the fault
Zone isolation, valve inspection and pressure testing narrow an underground leak to a run before anything is excavated.
Repair, test, tidy
Valves rebuilt or replaced, pipe repaired, wiring re-spliced in waterproof connectors, then the zone re-run and the ground backfilled properly.
Coverage
Irrigation work by region
Pressurized irrigation repair concentrates in the Treasure Valley, where the separate delivery system exists. In the ditch and canal country along the western border and across the Snake River Plain, sprinkler systems run off household supply, a well or surface water, the piping still fails the same way, but the shutoff and the season are different.
Questions
Irrigation repair questions
That pattern is the clearest sign you have separately-delivered pressurized irrigation, and that the problem is on that system rather than your household supply. Common causes are a seasonal shutdown, a closed point-of-delivery valve, a failed zone valve, a clogged filter or freeze damage at the backflow assembly. It is also possible the district simply has not turned the water on yet.
If it stays wet when the sprinklers have not run, you have a mainline leak, the section that is pressurised whenever supply is open. That runs continuously and it is metered, so it is worth treating as urgent. If the patch only appears after a particular zone runs, it is a lateral leak on that zone, which is less urgent but still worth locating before the ground opens up.
Close the isolation valve on the manifold for that zone if there is one, or shut the irrigation supply at the point of delivery. Then call. A stuck-open zone valve is usually debris under the diaphragm or a failed solenoid, and it is generally a rebuild rather than a replacement.
Almost always. Zone isolation, surface evidence and pressure testing narrow the search to a run and usually to a section, so the excavation is a hole rather than a trench across the garden. Where the surface gives nothing away, testing sections in isolation identifies which one is losing water before any digging starts.
No. The plumber repairs and replaces backflow assemblies, but certification testing is a separate service and the requirements differ by district and city across Idaho. Your irrigation provider or water utility can tell you who performs testing locally and how often it is required for your property.
Repair is usually right for isolated failures, even several of them, because irrigation components are individually inexpensive. Replacement starts to make sense when the mainline itself is failing repeatedly, when the layout no longer matches the landscape, when heads have been added piecemeal until zones are unbalanced, or when a system installed decades ago has reached the point where every visit finds something new.
Pressure too high for the nozzles. Misting wastes a great deal of water to evaporation and drift, and it stresses the whole system. The fix is usually pressure-regulating heads or a regulator at the zone, and it typically pays for itself in water, particularly on a metered household supply.
That is low-head drainage: after the valve closes, the water left in the lateral drains out through the lowest heads on the slope. It looks like a leak and it is really gravity. Check valves in the affected heads solve it, and it is worth solving, because repeated saturation in one spot kills the lawn there.
Not sure if it's your system or the district's? We'll tell you.
Charge it slowly. Then find out what winter did.
Most irrigation repairs are small if they are found at startup and expensive if they are found in July, after the water has been running into the ground for two months.
(833) 472-2088