Question
QUESTION: I'm capturing rainwater in half a dozen rain barrels around the house.  I'd like to install electrically initiated valves to control the attached drip irrigation, but the water pressure is too low to use diaphragm based irrigation valves (when the water level in the barrels is low, it has less than 1 psi and I understand that diaphragm valves require at least 5 psi).  Is there a manufacture of electrically initiated valves that will work with typical irrigation controllers and function at such a low pressure or do I need to install a pump at each barrel to make this work?

ANSWER: You might try the Irritrol 2500 or 700 series valves.  
http://www.irritrol.com/valves/valves.html



---------- FOLLOW-UP ----------

QUESTION: Jeff - Thanks for the suggestion.  I did check both the spec sheets and an Irritrol dealer.  The spec sheet indicates that both valve series require 10 psi and the dealer suggests that they may work as low as 5 psi, but even at the lower pressure I'd need to have the water barrels elevated to roughly 12 feet (5 psi/0.43 psi/ft).  That's almost 4 feet higher higher than the rain gutter.  Is anyone aware of a 3/4" of 1" ball or gate type electrical valve that will work with a standard controller?  There seem to be plenty of rain barrels for sale.  Are all of those drained with manual valves?

Answer
I dont know much about this, because where I live it is not an issue.  But I seem to recall that people used to use a small pump, like a cooler pump, to get the flow they needed.  You might check with some of the organic gardening magazines and journals.