Question
QUESTION: we have to cut water by 30% starting next mo. we changed all our sprinklers to 17gph and our pressure gage is 20 to 22.
question. does anyone know how long we have to water avocado trees so they do not die? is once a week o.k.? 8 hrs?
we have 150 sprinklers. how much water would that be.
sorry but we do not know what is o.k.

ANSWER: The best measure of how much water you need to apply is by the evaportanpoation (eT) rate.  For my area of the country,the  ET for October was about 3.5 inches, so you would need to apply the equivalent of 3.5 inches of water to your soil.  You can calculate the inches per hour you are applying by putting a small flat container in the area where your sprinklers are operating, and let them run for an hour.  Then you can see how  much water is applied in one hour.  Then you can space this out in weekly applications.

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

QUESTION: thank you so much. this is fallbrook. is this the same ratio?
i will do the flat container thing tomorrow.

Answer
It would be similar to Fresno, but not exactly the same.  Follow this link to CIMIS, the organization that collects and distributes data regarding ET for most California areas.  It may be a valuable resource for you.  

http://www.cimis.water.ca.gov/cimis/welcome.jsp