What To Include In An Irrigation Audit For New Hampshire Properties

Introduction: purpose and scope of an irrigation audit

An irrigation audit for New Hampshire properties is a systematic evaluation of an irrigation system to measure efficiency, detect waste, and recommend improvements that respect local climate, soils, water supplies, and regulations. The goal is to balance plant health and landscape goals with water conservation, cost reduction, and risk management related to freeze-thaw conditions common in New England.
A thorough audit covers equipment, hydraulics, distribution uniformity, scheduling, and documentation. It identifies immediate fixes and longer-term upgrades, providing actionable recommendations for homeowners, property managers, golf courses, and commercial landscapes in New Hampshire.

Why New Hampshire deserves a tailored approach

New Hampshire has cold winters, variable precipitation, and a mix of soil types from rocky glacial till to well-drained sands near the seacoast and river valleys. Municipal water restrictions, seasonal drought risk, and the need for reliable winterization make generic irrigation audits insufficient.
An audit must consider:

Source of irrigation water (municipal, well, surface water).
Backflow prevention and local testing requirements.
Freeze protection and winter shutoff procedures.
Soil infiltration rates and available water capacity.
Landscape use patterns: turf, ornamentals, native plantings, erosion control.

Pre-audit preparation

Before visiting the site gather:

Site plans or as-built irrigation drawings if available.
Water bill history and meter readings for at least 12 months.
Records of past repairs, head types, and controller programming.
Local watering restrictions or permit requirements.

On arrival, interview the property owner or manager to understand complaints, observed leaks, plant stress, and preferred turf/plant standards. That context focuses the technical inspection and helps prioritize recommendations.

Visual inspection: what to look for

A visual walk-through is the fastest way to find obvious problems. Key items to inspect visually include:

Sprinkler head type and condition: rotor, spray, bubbler, drip emitters.
Head spacing and alignment: heads should be perpendicular to area and set at correct height.
Signs of leaks: wet spots, soggy soil, unexplained turf green patches.
Mainline and lateral trenches: exposed pipes, cracked fittings, replaced segments.
Backflow preventer: presence, enclosure, freeze protection, labeling.
Controller and wiring: age, programming, rain sensor, freeze sensor.
Valves and valve boxes: cracked bodies, silt in boxes, root intrusion.
Drainage and runoff paths: observation of water leaving the site during runs.
Remote water sources: ponds, streams, or hydrant connections and screens.

Hydraulic and flow testing

Quantify capacity and pressure so system components work within design ranges.

Measure static pressure at the spigot or controller connection using a gauge; record psi.
Record dynamic pressure while one or more zones are operating; note pressure drop.
Measure flow rate from irrigation meter or hydrant using a bucket test where appropriate, or by reading flow meter if available. For meterless systems, calculate flow from pump specifications or well capacity.
Compare measured pressure and flow to manufacturers’ head pressure requirements: many spray heads operate best around 30-45 psi; rotors often operate between 25-50 psi. Excess pressure can cause misting and losses; low pressure causes incomplete coverage.
Document pump operation if present: start/stop cycles, pressure tank status, and well recovery rate. Low well recovery or frequent cycling can be a critical constraint especially in rural New Hampshire properties.

Distribution uniformity and catch-can testing

Distribution uniformity (DU) quantifies how evenly water is applied across a zone. A simple catch-can test is practical and effective.

Place 8 to 24 catch cans or straight-sided containers in a grid that represents the head pattern in the zone. Place cans centered between heads and evenly across the wetted area.
Run the zone for a set time, commonly 15 minutes, ensuring the system has been recently adjusted to typical operating pressure.
Measure the depth in each can. Calculate average of all cans (A) and average of the lowest 25 percent of cans (LQ). DU = (LQ / A) * 100.
Target DU values: 70% or higher is reasonable for spray systems; rotors can achieve 70 to 85% if properly matched and maintained. Low DU indicates head spacing, nozzle mismatch, pressure variation, or clogged heads.
Use results to recommend nozzle swaps, pressure regulation, or layout changes. For example, converting mismatched spray heads to matched nozzles or introducing rotors for larger turf areas can improve DU and reduce run time.

Run time and precipitation rate calculations

Determine how long zones need to run based on precipitation rate and plant water requirements.

Calculate precipitation rate (inches per hour) from the catch-can data: total depth averaged across cans divided by run time in hours.
Match precipitation rate to soil infiltration rate to avoid runoff. Sandy soils in some coastal or riverine sites accept higher rates; rocky or compacted soils require lower rates and potential cycle-and-soak scheduling.
Account for crop evapotranspiration (ET) and New Hampshire seasonal variations. In July and August, ET is highest and irrigation needs increase; in spring and fall, fewer supplemental irrigations are required.
Recommend scheduling that uses early-morning run times (typically before 8 AM) to reduce evaporation and disease pressure. Provide example schedules: a turf zone with a precipitation rate of 0.8 in/hr and a need for 0.6 inch/week could run two cycles of 20 minutes spaced a day or two apart, adjusted by soil type.

Controller, sensors, and smart scheduling

Controllers are the primary tool for water management.

Verify controller model and date code; older electromechanical timers lack flexibility. Recommend replacing controllers older than 10 years or those without weather or ET scheduling capability.
Test rain sensors, freeze sensors, and soil moisture sensors for correct operation and placement. A rain sensor installed too high or too exposed may not register localized rain.
Recommend moving toward smart controllers or adding ET-based scheduling that factors recent weather, local historical data, and plant types rather than fixed days-per-week schedules. Smart controllers can reduce water use significantly, especially in variable New Hampshire seasons.

Backflow prevention and regulatory compliance

Backflow prevention is mandatory for most connections and protects drinking water.

Confirm a properly sized and installed backflow preventer is present and accessible. Many municipalities require annual testing of reduced pressure zone (RPZ) or double check assemblies.
Inspect for freeze protection: RPZs should be inside heated enclosures or otherwise protected from temperatures that cause damage.
Document test tags, last test date, tester license number (if available), and recommend retesting if records are missing or out of date. Noncompliance can result in fines and water shutoffs in some communities.

Soil, plant material, and runoff assessment

Soils strongly influence irrigation strategy.

Perform a soil probe at representative locations to determine texture, restrictive layers, and depth to bedrock.
Record infiltration observations: percolation speed, presence of perched water, and slope.
Map plant types and turf targets. Native plant beds, ornamentals, and high-use turf areas have different irrigation demands. Recommend transitioning lower-value areas to drought-tolerant species where appropriate.
Identify erosion-prone areas where irrigation may exacerbate slope instability and suggest alternatives like drip irrigation or slower application rates.

Winterization and freeze protection

Winter freeze-thaw in New Hampshire can severely damage systems left wet.

Verify winter shutoff procedures and timing. Recommend blowing out lateral lines with compressed air to a safe maximum pressure as specified by manufacturers and local practices; typical blowout pressure ranges from 40 to 80 psi but should never exceed head or pipe ratings.
Ensure valve boxes, backflow preventers, and above-ground components are drained or insulated.
Inspect for components susceptible to heaving or breakage during freeze cycles and recommend anchoring or burial depth adjustments where possible.

Reporting and prioritized recommendations

A useful audit report is concise and prioritized.

Include an executive summary with immediate safety and compliance issues (leaks, backflow failures, major pressure problems).
Provide a prioritized list: immediate fixes, short-term improvements (0-2 years), and long-term upgrades (3-5 years).
Supply cost ranges and expected water savings for each recommendation to help owners make informed choices.
Include a simple maintenance schedule: seasonal startup, mid-season inspection, annual catch-can test, controller check, and winterization timeline.

Sample checklist for a New Hampshire irrigation audit

Verify site documents, water bills, and recent repairs.
Walk property; inspect heads, valves, piping, and backflow preventer.
Measure static and dynamic pressure; perform flow test.
Run catch-can test and calculate distribution uniformity and precipitation rate.
Probe soils and note infiltration and compaction.
Inspect controller, sensors, and wiring; evaluate for smart controller upgrade.
Check pump and well recovery if applicable.
Inspect for leaks, runoff, and drainage issues.
Verify winterization procedures and backflow freeze protection.
Deliver written report with prioritized recommendations and cost estimates.

Practical takeaways and recommended frequencies

Perform a full irrigation audit annually or when you notice plant stress, rising water bills, or after system modifications.
Use catch-can tests for every turf zone at least once per year and after major nozzle or pressure changes.
Test backflow preventers annually where required and ensure they are frost-protected.
Adjust scheduling seasonally: reduce run times in spring and fall, increase in hottest months, and suspend irrigation during natural precipitation that meets landscape needs.
Prioritize fixes that improve distribution uniformity: nozzle matching, pressure regulation, and repair of damaged heads. Improving DU is often the most cost-effective way to reduce water use while maintaining landscape quality.

Conclusion

A comprehensive irrigation audit for New Hampshire properties combines visual inspection, hydraulic testing, distribution uniformity measurement, soil and plant assessment, and an evaluation of controller and regulatory compliance. The audit should produce a prioritized action plan focused on safety, code compliance, water conservation, and system reliability through harsh winters and variable summer conditions. Frequent checks, smart scheduling, and targeted upgrades produce the best outcomes: healthy landscapes, lower bills, and reduced environmental impact.