When I moved into my home, the front lawn had an automatic sprinkler system, but not the back. After two years of a perfect front lawn and dragging the hose to the back, I decided to add two more zones onto the existing system.
The procedure is really simple, I used 3/4 inch plastic pipe from the valves to the sprinkler heads. It costs about $9.00 for a 100 foot coil of the pipe. Code in most cities requires the use of anti-syphon valves. Rainbird sells these for around $20 and they are the valves you use to turn on and off each zone (area you wish to water). They can be turned on manually or you can hook up a sprinkler timer and they will turn on automatically (these are great!!!) The anti-syphon prevents the water within the sprinkler system from backing up into the house water supply.
I wanted three zones, one for the front, one for the back and one for the gardens so I had to make a manifold from 3/4 inch copper pipe. It's basically a water supply line with the three anti-syphon valves screwed into it. To make the manifold, I bought 2 "t" fittings, one 90 degree elbow and about 2 feet of copper pipe (everything was 3/4 inch). I put it together so the valves were on the top of the "t" one after the other with the elbow leading to the last valve. Then I connected the open end of the manifold to the water supply. (make sure you place the "t's" and elbows far enough apart so you can screw in each valve without bumping into the one next to it :)
From each of the valve, I ran the plastic pipe a few inches below the ground to the sprinkler heads. When you buy the heads there are instructions on how close together to place them for certain pressure ratings. (I used three impulse heads $8.00 each for each zone of the lawns, and 10 of the 59 cent pop ups for the gardens and have plenty of pressure and coverage.
Because my property is on a slight slope, and I live in Chicago, I installed a fitting at the lowest point of the yard in each zone so I could drain the system in the fall without a compressor.
Take a trip to your local hardware store and get some free planning guides from the sprinkler display. They will help you determine what you need.
This project was soooo easy I surprised myself! And if you do it yourself, it's inexpensive. A three zone system with 16 sprinkler heads, 300 feet of plastic pipe, three anti-syphon valves, a sprinkler timer (the most expensive part) and the fittings and clamps cost less than $250 for the parts. I was real lucky and I payed even less because I managed to get most of the parts from Builder's Square as they went out of business (75% off)