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What is Smart Irrigation?

In the United States, outdoor water use alone averages more than 9 billion gallons of water each day, mainly for landscape irrigation. As much as 50% of this water is wasted due to overwatering caused by inefficiencies in traditional irrigation methods and systems. Smart irrigation technology is the answer.

Smart irrigation systems tailor watering schedules and run times automatically to meet specific landscape needs. These controllers significantly improve outdoor water use efficiencies. Unlike traditional irrigation controllers that operate on a preset programmed schedule and timers, smart irrigation controllers monitor weather, soil conditions, evaporation and plant water use to automatically calculate new watering schedules every day.

The experts agree that smart irrigation systems and controllers versus traditional irrigation controllers conserve water. Several controlled research studies indicate substantial water savings from 40% to 70%. Tests by the Irrigation Association (IA) and the International Center for Water Technology at California State University in Fresno, have shown smart irrigation controllers to save up to 20% more water than traditional irrigation controllers.

The Difference Between Weather-based and Soil Moisture Sensor-based Smart Irrigation Systems

Essentially there are two types of smart irrigation controllers: weather-based (ET) and soil moisture sensor-based. Both can help you save water, but there are important differences. Here’s some information on both technologies to help you choose the system that best meets your needs.


Weather-based controllers, also known as evapotranspiration (ET) controllers, use local weather data to adjust irrigation schedules. On a daily basis, a weather station or remote weather service monitors conditions such as temperature, wind, solar radiation and humidity for your property. Smart irrigation controllers combine that data with site-specific variables such as soil type and sprinkler application rate to adjust watering run times or schedules. It’s a very accurate way to calculate landscape water needs. There are three basic types of weather-based ET controllers:

  • Signal-based controllers use meteorological data from publicly available sources to calculate unique localized ET values. The ET data is then sent to thousands of controllers through a wireless connection. Some weather services deliver highly accurate local data down to the square kilometer, eliminating the need to maintain an on-site weather station.
  • Historic ET controllers use a pre-programmed water use curve, based on historic water use in different regions. The curve can be adjusted for temperature and solar radiation.
  • On-site weather measurement controllers use weather data collected on-site to calculate continuous ET measurements and water accordingly.

Click here to learn more about weather-based irrigation controllers.


The other type of smart irrigation controller is soil moisture sensor-based. Sensors buried in the root zone of turf, trees or shrubs accurately measure the moisture level in the soil and transmit this data to the controller. The controller then adjusts the pre-programmed watering schedule as needed. There are two types of soil moisture sensor-based systems:

  • Suspended cycle irrigation systems use traditional timed controllers and automated watering schedules, with start times and duration. The difference is that the system will stop the next scheduled irrigation cycle when there is enough moisture in the soil. However, if the soil is too dry, it will not adjust the  schedule to water more. Many of these sensors can be added to an existing traditional controller.
  • Water on demand irrigation requires no programming of irrigation duration (only start times and days of the week to water). This type maintains two soil moisture thresholds – high and low – and automatically calls for water as needed to maintain soil moisture between the two. When properly calibrated, this can be an extremely efficient set up.

Click here to learn more about soil moisture sensor-based irrigation systems offered by Baseline Irrigation Solutions, a HydroPoint company.