Tested Products

Soil Moisture-Based Controllers

Soil moisture-based controllers shut off the irrigation system when the ground is already wet, preventing overwatering. These smart controllers use a probe to measure moisture at the root zone. The system compares this reading to the recommended moisture level for the plant, soil type and other variables that were programmed in when the controller was first installed.


If the amount of moisture in the soil meets or exceeds the target level, the controller overrides the irrigation system. When the sensor detects dry conditions, it allows the system to operate as programmed. Soil moisture-based controllers can be retrofitted on installed irrigation systems.


SWAT Testing Protocol

SWAT began developing a testing protocol for soil moisture-based controllers in April 2003. Version 3.0 of the protocol was approved and adopted in August 2011.  


Product Testing Results

07/30/2009 Acclima ACC-SEN-TDT 

08/27/2008 Acclima Digital TDT Sensor 

07/08/2010 Baseline BL-5315B 

07/08/2010 Baseline S-100 

11/03/2008 Decagon ECH2O EC-5 

04/10/2010 Delta-T SM200 Moisture Sensor 

08/27/2008 Irrometer Watermark 

09/30/2010 Rain Bird SMRT-Y08 

08/31/2012 UgMo ProHome PH100WS 


For questions about SWAT or soil moisture-based controllers, contact the Irrigation Association (703.536.7080; swat@irrigation.org).