Sprinkler Zone Failing in Northern Colorado? Repair, Replace Just the Zone, or Reline the Yard

The honest answer in one paragraph

One failing zone is almost always a $150–$300 repair. Three or more failing zones on a 15-year-old system usually tip toward a $1,500–$3,000 zone replacement or a $5,000–$9,000 full re-line. The middle path — replacing one zone cleanly while the rest is healthy — is the right call more often than people expect.

The 4 paths, and what each one actually costs

Path 1 — Repair the zone ($150–$300)

This is the right call when one head is broken, one fitting is cracked, the solenoid won't open, or a small section of poly pipe has split at a fitting. Signs you belong here:

• The rest of the zone runs fine and the heads pop up normally.
• You're seeing one wet spot, one sunken head, or one head that's dead.
• The valve manifold is accessible and quiet — no gurgling, no leak at the solenoid.
• The system is under 10 years old and you've had no other zone issues this season.

A typical NoCo visit covers one of the items above and runs $150–$300, often less if we can bundle it with the September prep visit or the October blowout on the same trip.

Path 2 — Replace just the one zone ($1,500–$3,000)

This is the right call when the lateral line is failing — multiple wet spots, persistent low pressure across the whole zone, brittle PVC that crumbles when you touch it, poly pipe that's been patched three times. Signs you belong here:

• The zone runs but coverage is patchy and the pressure is visibly low.
• You've repaired the same zone twice in the last three seasons.
• The valve for this zone won't hold — water keeps running after the controller shuts off.
• The rest of the system is intact and the other zones run fine.

A single-zone replacement in NoCo clay-loam runs $1,500–$3,000. The clay is what drives the cost: trenching is slower, the soil won't compact the same way sandy soil does, and most NoCo lots have an extra 6–10 inches of clay over the road base that has to come out before the new line goes in. Sandy soils trench for $300–$500 less per zone; that's not us, that's the dirt.

Path 3 — Reline or full system replacement ($5,000–$9,000)

This is the right call when the system itself is at the end of its life. You're here if the system is 15+ years old with poly pipe instead of PVC, two or three zones are failing at the same time, the valve manifold is leaking from multiple ports, the backflow preventer is original equipment, or the controller is a 2005-vintage mechanical timer that won't communicate reliably.

A full re-line for a 6–10 zone yard runs $5,000–$9,000 in NoCo, with most quotes landing in the $6,500–$8,000 range. That includes new PVC laterals, new valve manifold, new heads, a modern controller, and a new backflow device. If you're staring at a 10-zone system and three zones are failing, the math usually works out to "spend the $7K now" rather than "spend $2K every fall for three more years patching the same thing."

Path 4 — Patch enough to get through one more season ($100–$400)

Sometimes the right answer is to do the minimum to get through the blowout and plan the real work for next spring. This is the honest call when:

• The system is at end-of-life but you've already budgeted for a re-line in May.
• The failing zone is one you don't actually need — a side yard, a back strip, a bed you've been planning to convert to drip.
• The fix is small enough that you can do it yourself and the only failure mode is "the zone doesn't run," not "the zone is flooding the foundation."

Cap the patch at 10% of the cost of the real fix. If the real fix is a $7,000 re-line, anything under $700 is reasonable patching money. If the real fix is a $2,000 zone replacement, anything under $200 is reasonable patching money. Past that, you're just delaying the same bill.

Reading the system before you spend money

Before you call anyone, run each zone by hand from the controller for 3–5 minutes and write down what you see. The notes matter more than the visit.

• Pressure fine, all heads pop, one wet spot: single repair, $150–$300.
• Pressure fine, one head won't pop: clogged or broken head, $40–$80 if DIY.
• Low pressure across the whole zone: leak in the lateral line. Walk the yard looking for a soggy strip before the first head — found one means a $200–$400 spot repair; not found means the line is failing and you're in Path 2 territory.
• Zone won't shut off: solenoid stuck open or valve diaphragm shot, usually a $100–$200 single-part repair, or $400+ if the manifold itself is cracked.
• Zone won't turn on at all: check the controller first (cheap), then the solenoid (cheap), then the wiring between them. Most "dead zone" calls are a tripped breaker or a disconnected wire — not a buried line failure.

If you've already done the September prep walkthrough and the troubleshooting checklist from our brown-spots post, you're halfway to the diagnosis already.

When to call a pro (and when not to)

• DIY is reasonable: popping up a sunken head, adjusting the arc on a rotor, swapping a clogged nozzle, re-plugging a wire at the controller.
• Call a pro: anything that requires a shovel, a PVC cutter, or a multimeter. Valve manifolds, lateral line repairs, solenoid swaps inside a flooded valve box, and backflow work all fall here.
• Always call a pro: backflow preventer work in most of NoCo requires a licensed backflow tester for the annual certification anyway. Bundling the test with any other work usually saves the second-trip charge.

A few honest warning signs that the call should be sooner rather than later: a wet spot that keeps getting bigger, water surfacing in the lawn with no recent rain, a sudden spike on the water bill, or a zone that keeps running after the controller says it's off. Those are the calls where waiting another week costs more than the visit.

The fall timing decision

If you're going to do zone work, the calendar matters. Trench work that sits through a wet September followed by a hard October freeze is the most expensive way to find out a line was leaking. The realistic window:

• Late September: last clean week for non-emergency zone work in NoCo. Soil is workable, no freeze risk, and most irrigation companies have open schedule before the blowout rush.
• Early October: still doable for Loveland, Berthoud, Longmont, Frederick, Firestone, but crews are pivoting to blowouts and the schedule fills up. Most NoCo blowout routes are fully booked by mid-October.
• Mid-to-late October: only emergency repairs make sense. Wait until spring for anything that requires trenching.

What Mow 4 U actually does on these calls

We don't do full system replacements — that's an irrigation specialty company job and we'd rather tell you that than do it badly. We do handle the smaller end of the spectrum:

• The September prep walkthrough and small repairs bundled with the visit.
• Single-zone repairs up to about $400 — bad head, solenoid, fitting, short lateral patch.
• The October blowout with a same-visit backflow test if you need one.
• An honest read on whether you're looking at a $300 repair or a $7,000 re-line — and which NoCo irrigation companies we'd trust with the bigger job.

Serving Northern Colorado: Johnstown, Berthoud, Loveland, Fort Collins, Windsor, Greeley, Milliken, Timnath, Severance, Mead, Longmont, Evans, Firestone, Frederick, Eaton, Ault, and surrounding areas.