Irrigation system installation: what to know

What the job involves, what changes the price, and what to ask a pro.

What irrigation system installation is

Irrigation system installation plans and builds a lawn or garden watering system with mainlines, valves, heads or drip lines, a controller and backflow protection, matched to the site's water supply. People hire it to build a new system, to replace a failing one, or to bring a large or mixed-use yard onto a single, planned system.

Signs you need it

  • Watering is uneven, with some areas drowning while others stay dry all season
  • The yard has no system and watering by hose takes too long and wastes water
  • Beds, trees and turf are on the same zones and are getting watered at the wrong rates
  • A new build or a regrade has left you with areas that the old system no longer reaches
  • You want a system that can run on a schedule and adjust with the weather

What the pro does

  • The designer tests the water supply for pressure and flow and maps the yard by sun, soil, slope and plant type
  • Zones are laid out by plant water needs, with heads or drip lines matched to each zone's shape and size
  • The backflow preventer, the mainline and the valves are set, and buried lines are located before any digging
  • Trenches are dug and the pipe is laid to the depths the design calls for, then the valves and controller are wired
  • Each zone is run, checked for coverage and leaks, and then the controller is programmed and the system is handed over with a zone map

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Total area and the number of zones needed to match plant water needs
  • Water supply pressure and flow, which decide the pipe size and how many zones can run at once
  • Soil type and rock, which change trenching effort
  • Type of watering used, such as spray heads, rotors, drip or a mix
  • Backflow preventer requirements and any testing the area requires
  • Controller type, from a basic timer to a smart system with a weather input
  • Trenching distance and the surfaces that must be crossed or restored

What a written quote should spell out

  • The zone map, with the number of zones and the watering type for each
  • The water supply test and what it means for the design
  • The pipe types, sizes and depths, plus the valves, heads and controller models
  • The backflow preventer model, and the permit and testing steps the job requires
  • Restoration of turf, beds and paving disturbed during trenching
  • The warranty on parts and labor, and who to contact if a zone fails

Questions to ask before you hire

  • Can you test the water supply first, and show me the pressure and flow results?
  • How do you group plants into zones, and why?
  • Which backflow preventer do you install, and who tests it?
  • What controller do you install, and can I adjust it myself?
  • How do you locate the buried lines and any existing system before trenching?
  • What is the restoration plan for turf, beds and paving?
  • Will you walk the zones with me before you leave, and show me how to shut them off?

Red flags

  • They design the system without testing the water supply
  • They put plants with very different water needs on the same zone
  • They skip the backflow preventer or treat it as optional
  • They dig without locating buried utilities or existing lines
  • They will not show a zone map before the work starts

What you can do yourself

A homeowner can plan the zones, sketch the layout, and choose the heads or drip lines on their own. Call a licensed irrigation contractor for tapping into the water supply, connecting the backflow preventer, trenching for the mainline, and any wiring to the controller, since these involve water pressure and electrical work. Do not dig near buried lines until they have been located.

Licenses and permits

Irrigation installation is commonly licensed in many areas, and the backflow preventer and its testing may be governed by separate rules. Check with your state or local licensing agency and your local water utility or permit office before you hire or install.

Irrigation system installation questions

Why does the installer need to test the water supply?

Water pressure and flow decide how many zones can run at once and what size pipe and heads the system needs. A design without a supply test can end up with zones that do not reach the pressure they need.

Do I need a backflow preventer for an irrigation system?

Many areas require one to keep irrigation water from flowing back into the drinking water supply. Ask the installer which device they use, where it goes and who tests it, and check your local water utility for the rules.

Can I add zones to an existing system later?

Sometimes, if the supply and the controller can handle it. Ask the installer to check the water supply and the controller capacity before you plan an expansion, so the new zones do not drop the pressure on the old ones.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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