I received the material for my gravity fed drip irrigation system this past week. The system I am using is from www.irrigray.com . Their site is a wealth of information. Before deciding on irrigrays drip approach I did a lot of research, http://oasisdesign.net/ , is a good starting point with a wealth of knowledge that isn't built on fad theories.
My system is basically a gravity fed laundry to landscape system, the starting point of which is a surge tank. Don't confuse this with a storage tank, gray water contains to many proteins and other nutrients and if held for more than a few hours will get funky. As you can see I am using a durable garbage can.
The kit came with a fitting to easily tap into the surge tank. I drilled a 3/4" hole approximately 3" above the bottom of the tank, inserted a tight fitting rubber grommet, and then inserted a fitting that was a force fit in the grommet thus creating a watertight seal. The other end is a standard barbed fitting for 3/4" poly irrigation tubing. The valve you see is only for system service and maintenance, when the system is in operation this valve will always be open.
As you can see that 3/4" poly line goes past my irrigation valves, along a ditch, then comes back up and is run above ground in my orchard area.
I still need to install a 400 micron filter somewhere in the line before it gets to the orchard area, then install the 1/2" dripperline that has 2 gph droppers installed every 12" along its length. I plan on doing all of that next week which should be right on schedule for the start of the irrigation season here in Vegas. I did see one of my trees beginning to put out the tiniest little leaves today.