Lexington has a watering restriction problem that most homeowners don't discover until July, when the town sends a notice and the timer in the garage has been running zone six at 9:01 AM every dry day since April. That's a violation. Every morning. All summer. The timer doesn't know. It was programmed in 2014 and hasn't been touched since. The MWRA knows. (The lawn is indifferent, which at this point is the least of your concerns.)
I've been installing sprinkler systems in Lexington since 2000. The town is MWRA-fed (Wachusett Reservoir water via the Cosgrove Tunnel), which comes with some of the strictest residential watering rules in Middlesex County. Odd/even days. No irrigation between 9 AM and 5 PM. Mandatory rain-skip after measurable rainfall. A smart controller handles all of this automatically. A 12-year-old timer handles none of it.
TL;DR: Sprinkler installation in Lexington costs $3,000–$8,000 depending on lot size and zone count. Lexington's MWRA watering restrictions make a smart controller almost mandatory. Most installs take one to two days. A permit is required. We handle the paperwork.
What sprinkler installation actually costs in Lexington
National sites will tell you "$2,000 to $10,000" and leave you to figure out which end you're on. That range is technically accurate and practically useless. Here's what we charge on real Lexington properties:
| Lot type | Zones | EMI price range | Typical timeline |
|---|---|---|---|
| Small 1/4-acre / Cape Cod (~12,000 sqft) | 4 zones | $3,000–$4,500 | 1 day |
| Average 1/2-acre (~15,000–20,000 sqft) | 6–8 zones | $4,500–$6,500 | 1–2 days |
| Larger colonial / over 1/2-acre | 8–12 zones | $5,500–$8,000 | 2–3 days |
Those numbers include everything: heads, valves, mainline, lateral lines, controller, backflow preventer, wiring, trenching, and cleanup. We don't do the "base price plus extras" thing where the final bill surprises you.
The national average from the Irrigation Association sits around $4,600 for a half-acre system. That's close to our mid-range. The catch is they're averaging in states where the frost line is 6 inches and there's no backflow testing requirement. Massachusetts adds cost for frost depth, permits, and annual backflow compliance. We explain every line item before we dig.
The MWRA restriction problem nobody warns you about
Every summer, Lexington issues restriction notices: no watering 9 AM – 5 PM, odd/even days, mandatory rain-skip after rainfall. And every summer, dozens of older Lexington irrigation systems run out of compliance, not because the homeowner doesn't care, but because the timer in their garage was set in April 2014 and hasn't been touched since.
Here's the math that gets people: a 7:00 AM start across 10 zones at 12 minutes per zone means zone 6 starts at 9:00 AM exactly. That's a violation, every dry day, all summer. The MWRA doesn't send a warning first.
A smart controller fixes this permanently. The Hunter Hydrawise we install programs MWRA restrictions into the schedule automatically. Odd days, odd zones. Even days, even zones. If it rained last night, the sensor tells the controller to skip today. You don't think about it. The system handles it. The Massachusetts rain sensor law has required rain sensors on new residential installs since 2009. A smart controller is just the 2026 version of that same compliance, except it actually works.
What makes Lexington soil different
Lexington soil varies more than most people expect. The area around the town center and toward Arlington sits on heavier clay, dense, slow-draining, holds water at the root zone longer. Head toward the Bedford line or out past Route 128 and you hit sandy glacial outwash, drains so fast the water's at root level for about 90 seconds before it's gone.
Two Lexington homeowners can have the same system, same brand, same install year, and one is overwatering while the other is underwatering. The same nozzles and run times that work on the clay side flood the sandy side. The same schedule that works on the sandy side leaves the clay-side lawn parched.
This is why we pull soil samples before designing every Lexington system. It's not optional. It's the difference between a system that works and a system that makes you call us in August because the back lawn looks like a topographical map of disappointment. (Which, for the record, is not the lawn's fault.)
Why a smart controller is almost mandatory in Lexington
Below five zones, a basic timer works fine. You can manage the MWRA restrictions manually if you're the type who actually adjusts the schedule seasonally. (Most people aren't. No judgement. I have a Tom Petty CD I've been meaning to replace since 2003.)
At six or more zones, which is most Lexington half-acre properties, the smart controller math is hard to argue with:
- Hunter Hydrawise installed: $200–$500 on top of the install
- Water savings: 20–40% off outdoor use, first season
- MWRA compliance: automatic odd/even and 9 AM–5 PM blackout
- Payback: two to three seasons on most Lexington properties
We carry Hunter Hydrawise, Rachio, and Rain Bird ESP-TM2 on the truck. Hunter is the dependable choice. Rachio has the better app. Rain Bird is the one that'll still be running in 2045. Pick based on which trade-off you care about, not whichever YouTube ad you saw last. (We install all three. We have opinions. We'll share them if you ask.)
What's included in a professional EMI install
Every Lexington installation includes:
- Site survey and soil assessment: we walk the property, check water pressure, pull soil samples, and map the zone layout before we dig
- Design: head placement, precipitation rate matching, pipe routing, valve box locations, controller placement
- Trenching and pipe installation: mainline at 10–12 inches to stay below the frost line, lateral lines at 8–10 inches, Schedule 40 PVC
- Heads: Hunter PGP rotors for large areas, Hunter MP Rotator or Rain Bird 1800 series for beds and narrow strips
- Valve manifold: Hunter or Rain Bird valves in accessible valve boxes, wired back to the controller
- Controller: basic Hunter or Rain Bird timer included; smart controller recommended for 5+ zones
- Backflow preventer: testable double-check or RPZ depending on Lexington's code requirements
- Wiring: 18-gauge direct-burial wire, properly spliced and waterproofed
- Startup and walkthrough: we run every zone, adjust every head, program the controller, and show you how it all works before we leave
- Cleanup: trench lines filled, sod replaced, gravel raked
The Lexington install timeline
Day 0 (before we arrive): You call us at 781-983-3739. We ask about your lot size, any existing landscaping, pool locations, fence lines, and whether you want a smart controller. We give you a ballpark over the phone and schedule a site visit.
Site visit: We walk the property, check water pressure at the hose bib, map the zone layout, and give you a written quote. No pressure. If you want to think about it, think about it.
Install day 1, We mark utilities (Call Dig Safe, it's the law in Massachusetts), trench the mainline and lateral lines, install the valve manifold, and run the wiring. On a quarter-acre lot, we're usually done by mid-afternoon.
Install day 2 (if needed): For larger lots or properties with complex layouts (fences, pools, garden beds), we finish head installation, connect the controller, install the backflow preventer, and run the startup walkthrough.
Total time: One day for most Lexington properties. Two days for larger or more complex layouts.
When to stop reading this and just call someone
If you're on a quarter-acre lot with no pool, no fence complications, and you want the front and back lawn covered, call us and we'll quote it in fifteen minutes. You don't need to read another article.
If you're on a half-acre or larger with mixed landscaping, a pool, garden beds, and a fence on three sides, the site visit matters. We'll walk it, design it, and show you exactly where every head goes before we dig.
If you have a 15-year-old system that mostly works but has a few tired zones, you probably don't need a full new install. You might just need targeted repairs. We'll tell you honestly. (I've talked more people out of new installs than into them. That's not a sales strategy. It's just what happens when the owner answers the phone.)
Honest pricing. No "starting at" nonsense.
| Lot size | Zones | Price range | Includes |
|---|---|---|---|
| 1/4 acre (Cape Cod) | 4 | $3,000–$4,500 | Everything listed above |
| 1/2 acre (colonial) | 6–8 | $4,500–$6,500 | Everything listed above |
| 3/4+ acre | 8–12 | $5,500–$8,000 | Everything listed above |
Smart controller upgrade: add $200–$500 (recommended for 5+ zones)
Permit fee: $50–$100 (we handle the paperwork)
Annual backflow test: $75–$125 (required by Lexington code, we coordinate)
We quote the exact number after the site visit. The price we quote is the price you pay. If the job turns out to be more complex than the phone call suggested, we stop, re-quote, and wait for "go ahead" before we continue. That's how it works when the owner is on the truck.
Straight answers.
Do I need to be home during the install? We prefer it for the walkthrough at the end, but the trenching and pipe work can happen while you're at work. We'll coordinate access for the water shutoff.
Will the trenching damage my lawn? We cut sod in strips, stack it aside, backfill, and replace it. The lines heal in two to three weeks during the growing season. You'll see the seams for about a month. After that, you won't.
What if my water pressure is low? We check pressure at the site visit. Most Lexington homes have 45–60 PSI at the hose bib, which is fine. Below 40 PSI and we'll discuss a booster pump or adjusted head selection. We don't install a system that won't work with your pressure.
Can you install around my septic system? Yes, but we need to know where it is before we trench. We'll mark it and route around it. If you don't know where your tank and leach field are, we can locate them.
What brands do you install? Hunter and Rain Bird for heads and valves. Hunter Hydrawise, Rachio, and Rain Bird ESP-TM2 for controllers. Watts and Febco for backflow preventers. We carry parts for all of them on the truck.
How do I maintain the system after installation? Annual spring start-up ($75–$175 depending on zones), annual winterization ($100–$150), and a mid-season check if you want one ($95–$125). Or grab the EMI membership at $410/year. It covers all three plus a service call and 10% off parts.
If your Lexington lawn has been surviving on a garden hose and optimism, call us at 781-983-3739. We'll walk the property, design the system, and give you a number that doesn't change when we're done. Twenty-five years digging trenches in this town. We probably know your soil better than your geologist does. (We definitely charge less.)
Ready to get your system handled?
EMI Irrigation — family-owned, serving the greater Billerica area and Southern NH.