top of page

The Unpowered Irrigation Controller for Solenoid Valves (UICSV) uses evaporation as a gauge to control irrigation rather than the static timer intervals in conventional devices. It works with ordinary irrigation solenoid valves of any size, one solenoid per controller, sprinkler or dripper systems.


After irrigation and as water evaporates from the soil, water also evaporates from the controller’s container. The water in the container eventually reaches a low level corresponding to the soil drying out. The controller opens the solenoid and irrigation begins. A dripper attached to the outflow pipe slowly refills the container while the irrigation system ‘refills’ the soil. When the water in the container reaches a high level corresponding to the required watering of the soil, the controller shuts the water off and the cycle restarts.


Once correctly calibrated, the UICSV only sends water when plants need it and does not overwater. It responds to the same local weather conditions as the soil. Deep or shallow watering, frequent or delayed watering – all can be accommodated. You don’t have to ‘turn it off’ over winter as rain and cooler temperatures keep the container from drying out. You can leave your irrigation system unattended for weeks on end.


A polyester cloth wicks water from inside the container to outside the container to evaporate and so the cloth is always wet.


An irrigation system with a conventional irrigation controller can be upgraded to an unpowered system where each solenoid valve is controlled by a UICSV. The conventional irrigation controller and the associated wiring become redundant.



  • Unpowered (no batteries, no wires, no solar panels, no electronics, no computers, and no WiFi)
  • If you upgrade to the UICSV, the conventional irrigation controller and associated wiring become redundant
  • Use for any size irrigation application
  • Use for sprinkler irrigation or drip irrigation
  • Use with PC (pressure compensating) drippers or NPC (non pressure compensating) drippers
  • Adjust the dripper discharge by adjusting the control dripper
  • Adjust the interval between irrigation events by adjusting the exposed surface area of the polyester cloth
  • Adjusting the dripper discharge does not affect the interval between irrigation events, and adjusting the interval between irrigation events  does not affect the dripper discharge
  • Responds automatically to on-site evaporation and rainfall
  • The irrigation frequency increases significantly during a heat wave
  • When it rains, water enters the container and delays the start of the next irrigation event
  • Provided the same drippers are used throughout the irrigation application (including the control dripper), the dripper discharge is independent of the water supply pressure
  • Water in the container is protected from debris, algae, mosquitoes and thirsty animals
  • UV resistant including the container and polyester cloth
  • Simple, unpowered, and low tech, and therefore fewer things can go wrong
  • Leave your irrigation application unattended for weeks on end

Unpowered Irrigation Controller for Solenoid Valves

    bottom of page