Irrigation & Sprinkler System Inspection: What Every Inspector Should Check

Spring is when the calls start: "Can you check the sprinkler system while you're there?" If you're a home inspector, irrigation systems are showing up on your scope of work more frequently — and having a solid sprinkler system inspection checklist separates the inspectors who add value from those who write "sprinkler system present, not tested."

Irrigation systems aren't complex, but they have a lot of components spread across the entire property. A systematic approach saves time, catches the issues that matter, and gives your clients actionable information. This guide walks through every component you should evaluate, what to look for, and when it's time to refer to an irrigation specialist.

Before You Start: System Overview

Before turning anything on, gather basic information about the system:

• Number of zones: Check the controller display or count the zone valves at the manifold. Residential systems typically have 4–12 zones.
• System age: Ask the homeowner or check the controller manufacture date. Systems over 15 years old have significantly more component failures.
• Water source: Municipal supply, well, or reclaimed water. This affects pressure expectations and backflow requirements.
• Season status: Is the system winterized? If you're inspecting during cold months or the system has been shut down, note that you couldn't perform an operational test and explain why.

Controller and Timer Inspection

The controller is the brain of the system. Start your sprinkler system inspection checklist here.

What to Check

• Power: Is the controller receiving power? Check for a lit display or status lights.
• Programming: Are zones programmed with reasonable run times? Typical residential zones run 10–30 minutes depending on head type. Look for obviously wrong settings (zones running for 90 minutes, or schedules set to water at noon).
• Rain delay/seasonal adjust: Does the controller have rain delay or seasonal adjustment features? Are they being used?
• Battery backup: Most controllers have a battery to maintain programming during power outages. Check if it's present and functional.
• Wiring condition: Look for corroded connections, damaged wire insulation, or evidence of rodent damage at the controller box. Outdoor controllers are especially vulnerable.
• Controller type: Note whether it's a basic timer, smart controller (Wi-Fi/weather-based), or commercial-grade unit. Smart controllers with Weather-Based Irrigation Controllers (WBIC) certification are increasingly common.

Common Findings

• Controllers programmed to water daily (most lawns need 2–3 days per week at most)
• Dead batteries — programming lost after power outage
• Corroded wiring terminals at outdoor controllers
• Controller set to "off" or "rain delay" indefinitely — system hasn't run in months

Zone-by-Zone Walkthrough

This is the heart of the inspection. Run each zone individually and walk the entire coverage area.

What to Check Per Zone

• Activate each zone from the controller — verify the zone turns on and all heads in that zone pop up and spray.
• Full coverage: Walk the perimeter of each zone. Are there dry spots? Gaps between spray patterns? Head-to-head coverage (where one head's spray reaches the next head) is the design standard.
• Run time: Let each zone run for at least 2–3 minutes. Some issues only appear after pressure stabilizes.
• Valve operation: Listen for the zone valve clicking on. Check the valve box — are valves accessible? Is there standing water in the box (indicates a slow leak)?
• Pressure consistency: Do heads spray strongly and evenly, or do some sputter and barely reach half their rated distance?

Common Findings

• Zones that don't activate (bad solenoid, cut wire, or failed valve)
• Uneven coverage — dry patches in the middle of a zone
• Pressure drop on zones furthest from the supply
• Valve boxes buried under soil or mulch (difficult to service)

Sprinkler Head Condition

Heads are the most visible — and most frequently damaged — components. Inspect every head you can locate.

What to Check

• Broken heads: Cracked, shattered, or missing heads. Lawn mowers are the #1 killer.
• Misaligned heads: Rotors spraying the sidewalk, driveway, or house siding instead of turf. Fixed spray heads aimed at fences. This wastes water and can cause moisture damage to structures.
• Sunken heads: Heads that sit below grade and don't fully pop up. Soil settlement and turf growth cause this over time. Sunken heads have reduced range and get clogged with debris.
• Head type consistency: Within a zone, all heads should be the same type (rotors or fixed spray). Mixing types in one zone causes uneven watering because they apply water at different rates.
• Clogged nozzles: Partially blocked nozzles create erratic spray patterns. Look for uneven fan patterns or misting instead of a clean spray arc.

Documentation Tip

Photograph every damaged, misaligned, or sunken head with a wide shot showing its location relative to the house and a close-up of the deficiency. Count the total affected heads — "3 of 14 visible heads are damaged" gives the client actionable information.

Backflow Preventer Testing

The backflow preventer keeps irrigation water (which may contain fertilizer, pesticides, or soil bacteria) from flowing back into the potable water supply. This is arguably the most important safety component of any irrigation system.

What to Check

• Presence: Is there a backflow preventer installed? It's typically near the water meter or where the irrigation supply line branches off. Common types: Pressure Vacuum Breaker (PVB), Reduced Pressure Zone (RPZ), and Double Check Valve Assembly (DCVA).
• Condition: Check for visible leaks, corrosion, freeze damage, and missing caps on test ports.
• Installation: PVBs must be installed at least 12 inches above the highest sprinkler head in the system and cannot have any downstream shutoff valves. Improper installation negates the protection.
• Testing: Most jurisdictions require annual testing by a certified backflow tester. Check for a current test tag. Note: home inspectors typically don't perform the actual backflow test — we document presence, condition, and whether current test documentation exists.

Common Findings

• Missing backflow preventer entirely (surprisingly common on older systems)
• PVB installed below grade or below the highest head — not providing protection
• No test tag or test tag expired by several years
• Freeze damage cracks on above-ground PVBs (winterization oversight)

Pressure Assessment

Water pressure affects every aspect of system performance.

What to Check

• Static pressure: If you have a pressure gauge, measure at the irrigation supply point. Residential systems typically operate at 40–65 PSI. Below 30 PSI, heads won't reach rated distances. Above 80 PSI, you'll see misting and premature component wear.
• Pressure regulators: Some systems have a pressure regulator at the supply or at individual heads (especially drip zones). Check that they're present where needed.
• Pressure loss between zones: If the last zone on the line has noticeably lower pressure than the first, it may indicate undersized supply piping, a partially closed valve, or a leak in the mainline.

Common Findings

• High pressure causing misting at spray heads (wastes water, reduces coverage)
• Low pressure on far zones — often a sizing issue that's been present since installation
• Pressure regulators missing on drip zones (drip lines are rated for 25–30 PSI)

Pipe Leaks and Mainline Condition

You won't see the pipes — they're buried. But you can see the symptoms.

What to Look For

• Wet spots when the system hasn't been running (mainline or lateral leak)
• Sinkholes or soft, saturated areas over known pipe routes
• Unexplained increase in water bills (ask the homeowner)
• Mud or debris shooting from heads — indicates a break in the lateral line
• Consistent pressure loss across all zones (mainline leak)

Documentation Tip

If you suspect a subsurface leak, document the location with photos and measurements relative to fixed landmarks (corner of house, fence post). This helps the irrigation technician locate the leak without exploratory digging.

Winterization Status

In freeze-prone climates, this is critical — and it's one of the most common causes of expensive irrigation failures.

What to Check

• Blowout status: Has the system been properly winterized (compressed air blowout)? In cold climates, any water left in lines, valves, or backflow preventers will freeze and crack components.
• Backflow preventer: Is it drained and/or wrapped for winter? Above-ground PVBs and RPZs are extremely vulnerable to freeze damage.
• Controller: Is it set to "off" or "rain delay" for winter? A controller that activates zones during freezing temperatures wastes water and damages the system.

Spring Startup Concerns

If you're inspecting during early spring, the system may not have been started up yet. Note this limitation. If the system is operational, watch for:

• Heads that don't pop up (frozen or cracked risers)
• Valves that weep or won't fully close (freeze-damaged diaphragms)
• Backflow preventer that fails to hold pressure (freeze crack)

Rain Sensor and Smart Features

Modern systems should have some form of rain shutoff — many jurisdictions now require them.

What to Check

• Rain sensor presence: Look for a small disc-shaped device mounted in an exposed location (roof edge, fence top). Verify it's connected to the controller.
• Functionality: With the system running, press or soak the rain sensor. The system should shut off. If it doesn't, the sensor may be bypassed, disconnected, or failed.
• Smart controller integration: If the system uses a weather-based smart controller, verify it's connected to Wi-Fi and receiving weather data.

Common Findings

• Rain sensor present but bypassed at the controller (there's usually a bypass switch)
• Sensor mounted under an eave where rain can't reach it
• Smart controller disconnected from Wi-Fi — running on manual schedule only

Drip Zones and Micro-Irrigation

Many systems include drip zones for garden beds, planters, and foundation plantings.

What to Check

• Pressure regulator: Drip zones need a pressure regulator (25–30 PSI). Without one, emitters blow out and tubing disconnects.
• Filter: Drip systems need an inline filter to prevent clogging. Check for presence and condition.
• Emitter output: Walk the zone and check individual emitters. Look for dry spots (clogged emitters) and flooded areas (broken tubing or disconnected fittings).
• Tubing condition: UV exposure degrades drip tubing over time. Look for brittle, cracked, or sun-bleached tubing that needs replacement.
• Coverage: Are all planted areas served? Drip zones should match the current landscaping — not the landscaping from five years ago.

When to Refer to an Irrigation Specialist

As a home inspector, you provide a general assessment. Refer to a licensed irrigation specialist when you encounter:

• Backflow preventer that needs certification testing — this requires specialized equipment and certification
• Suspected mainline breaks — locating and repairing buried pipes requires specialized equipment
• System redesign needs — coverage gaps that can't be fixed with simple head adjustments
• Commercial or large systems — systems with 15+ zones, booster pumps, or central control systems
• Well-fed systems with pressure issues — may need pump evaluation
• Smart controller programming — complex schedules, flow monitoring, and water budgeting

Documentation Tips for Your Report

Clear documentation makes the difference between a useful irrigation assessment and a throwaway paragraph.

Structure Your Findings

• System overview: Number of zones, controller type, water source, backflow type
• Zone-by-zone summary: Working/not working, coverage quality, head conditions per zone
• Safety items: Backflow preventer status, pressure concerns
• Maintenance items: Misaligned heads, clogged nozzles, programming recommendations
• Recommend further evaluation: Specific issues that need a specialist

Photo Approach

• Wide shot of the controller showing programming
• Each deficient head (location + close-up)
• Backflow preventer condition
• Any wet spots or suspected leak areas
• Valve box condition

For more on exterior documentation, see our Exterior Inspection Checklist.

Narrate Your Findings, Don't Type Them

Walking a property's irrigation system means you're moving — zone to zone, head to head, covering the entire lot. Stopping to type notes on a tablet kills your efficiency.

ReportWalk lets you dictate findings as you walk each zone. "Zone 3, two rotors misaligned spraying the driveway, one head cracked at the base, coverage gap in the southwest corner." Voice-to-report captures it, structures it, and you're already walking to Zone 4.

Available on iOS. Built for inspectors who cover ground.

Irrigation inspection is a natural add-on service that clients appreciate and competitors skip. Build a systematic checklist, invest 15–20 minutes per inspection, and you've differentiated yourself with a service that generates referrals — especially in spring.