Many landscape managers and irrigation professionals track total water use from utility bills but often lack visibility into how much water actually goes to irrigation. Without this insight, sites may unknowingly overwater, leading to waste, runoff, and landscape damage—issues that not only harm plant health but can also cause flooding, erosion, and damage to hardscapes.
Understanding exactly how much outdoor water a property uses is the first step toward improving irrigation efficiency. A water audit helps identify overuse, leaks, and inefficiencies, ensuring that landscapes receive the right amount of water—not too much, not too little.
The key to responsible irrigation management is following the Landscape Irrigation Requirement (LIR)—the precise amount of water a landscape needs to stay healthy without waste.
In this blog, we’ll break down:
- What LIR is and how it’s calculated
- How to determine if your site is overwatering
- How smart irrigation systems ensure properties irrigate only what’s needed—protecting landscapes while reducing water waste
What is the Landscape Irrigation Requirement (LIR)?
The Landscape Irrigation Requirement (LIR) is the precise amount of water a landscape needs to stay healthy while avoiding overwatering. It accounts for climate, plant types, soil conditions, and irrigation system efficiency—helping landscape managers apply just the right amount of water without waste.
Many properties irrigate based on fixed schedules rather than real-time landscape needs, leading to excess water use, runoff, and unnecessary strain on local water supplies. By calculating LIR, landscape professionals can improve irrigation efficiency, maintain plant health, and reduce water waste.
How LIR is Determined:
- Map Data Analysis: Satellite imagery provides a detailed view of the landscape, including terrain features, vegetation types (turf, trees, shrubs), and total irrigable area. Advanced mapping tools help measure landscaped square footage in acres or square feet, ensuring accurate calculations.
- Effective Evapotranspiration (ET) Analysis: ET represents the water lost from soil evaporation and plant transpiration, adjusted for rainfall and is a critical factor in determining LIR. Using HydroPoint’s Climate IQ ET, hourly ASCE Penman-Monteith ET data is calculated for different microclimates, ensuring irrigation aligns with real-time landscape needs.
- Crop Type Analysis: Different plants have unique water needs, determined by crop coefficients (Kc), which vary based on plant type, growth stage, and local climate conditions. For example, turfgrass requires significantly more water than drought-tolerant or native plants, leading to different LIR values across a property.
- Irrigation System Efficiency: LIR also factors in irrigation system performance, measuring distribution uniformity, runoff potential, and evaporation losses. Systems with optimized scheduling and modern technology can improve efficiency by ensuring water reaches plants effectively without excess waste.
By calculating and applying LIR, landscape managers can optimize irrigation schedules, reduce excess water use, and minimize their outdoor water footprint. Smart irrigation systems help properties avoid overwatering, reduce waste to maintain healthy landscapes—all while conserving water and lowering costs.
Case Study: Smart Irrigation in Action
Adobe Creek Homeowners Association in California implemented HydroPoint’s WeatherTRAK smart irrigation system and achieved a 30% reduction in outdoor water use, saving 9.1 million gallons annually and cutting water costs by $44,000 per year—all while maintaining healthy landscapes.
This proves that applying LIR with smart irrigation technology is essential to water stewardship and efficiency.
How HydroPoint Calculates LIRs
For properties looking to improve outdoor water efficiency, HydroPoint offers a free HydroAnalysis—a pre-sales water audit that evaluates current irrigation use and identifies potential savings from smart irrigation technology.
Many schools, municipalities, and commercial sites lack visibility into how much water their landscapes actually need versus how much they currently use. A HydroAnalysis provides a clear, data-driven assessment of a site’s irrigation footprint, helping decision-makers understand the impact of watering only to the Landscape Irrigation Requirement (LIR).
How HydroPoint’s HydroAnalysis Works:
- Historical Water Bill Review: Assessing 12 months of irrigation water use to establish the site’s current outdoor water footprint.
- Landscaped Area Mapping: Using Google Maps and satellite imagery to classify plant types and irrigated acreage.
- Evapotranspiration & Climate Data Integration: Factoring in regional weather conditions to calculate true water demand.
- Irrigation System Efficiency Evaluation: Identifying inefficiencies in irrigation delivery, from outdated scheduling to equipment performance.
The end result is a custom savings estimate, showing how much water, money, and time the site could save by switching to HydroPoint’s smart irrigation controllers, which automatically irrigate to the LIR.
Take Control of Your Irrigation
Understanding how much water your landscape actually needs is the key to efficient irrigation management. By calculating Landscape Irrigation Requirements (LIR) and implementing smart irrigation technology, properties can eliminate waste, reduce water use, and maintain healthier landscapes.