I found this on the University of Florida website. 1001 ways to have a really bad irrigation system 1) Undersize your source of water: Select a pump that can just barely supply your smallest zone when the system is first installed. 2) Doom the suction line: Install the suction line near a fast growing tree. Within a few years, roots will push the line up out of the ground, so you'll always know where it is. That also helps aerify the irrigation water. The pump is guaranteed to suck air, if you can ever get it primed. 3) Mix, don't match: Use a combination of high precipitation spray heads and low precipitation rotary heads within the same zone. This ensures that dry spots dry out while wet areas drown. 4) Bury your valves: The easiest way of covering a valve is to just bury it. This way it will never be an esthetic nuisance, and if anyone ever does find it again, the handle will be so corroded it will just break off and not be a problem. 5) Provide vertical irrigation: South Floridians are accustomed to rust-stained walls. It's almost a badge of honor to have an expensive plate-glass window that you can't see out of, or a fancy corporate sign that is tarnished in rust. You can contribute to this phenomenon by placing undependable impact drive heads close to walls. The painters will enjoy steady employment, year after year. 6) Use the smallest pipe size you can find:The tighter you squeeze water, the higher the pressure. You can prove this rule of physics by putting your thumb on the end of a hose and seeing how much farther the water squirts. Use even smaller pipes on long, narrow runs: This creates an attractive geometric series of green oases surrounded by brown. 7) If you have to use valve boxes, bury them, too: While placing the top of the valve box two or three inches deep is enough to hide it, deeper is better. In fact, you should place the valve box directly on top of the pipe, so that the pipe will support the valve box when you drive over it. 8) Mister heads need 80-100 pounds pressure: Why else are they called misters? 9) Water at about 4 p.m.: This way you can see if the sprinklers are working when you drive home. Besides cooling the grass, motorists and bicyclists appreciate a refreshing shower. 10) When digging a trench, only wimps and nerds need a string line: The stronger irrigation technicians should be able to wrestle 4-inch PVC pipes into the most crooked ditch, gluing so-called straight fittings at incredible angles. 11) Use extra glue to cover gaps in pipes: Whether you think you got some sand in the fitting or you see a crack that just won't close, keep putting as much glue as possible on the outside as a form of insurance. 12) Space sprinklers twice their diameter: If the droplets from one sprinkler just touch the droplets from next sprinkler, you've got perfect coverage. 13) Extend the pipe to prevent breakage: If you have pipes breaking due to water hammer, you need to use a tee to extend the ends of the pipes beyond the sprinklers to take the stress. 14) Always use schedule 40 pipe: No matter the size of the pipe, schedule 40 is right. 15) Use both a foot valve and a check valve: This prevents leaks in the suction line.