If you are looking for an Irrigation guy, look no further than Randy at A1 Lawn Sprinklers, LLC. I have worked with on several occasions and I have gotten consistently great feedback from my customers.
The pump system is dependent upon need. With a well that is dedicated to providing water for irrigating a lawn, most commonly we will use a 1 HP 20 GPM pump. For a residence that is not on a municipal water supply, we will use a Grundfos 22SQE Constant pressure system with a CU301 control box (pictured).
It is common to drill wells in municipalities in order to have an economical way to water your lawn. In Wisconsin, you may need to have an annual inspection to ensure that the well is code compliant and there are no cross connections and a bacteria sample may be necessary.
If you use 2.5 gallon per minute @ 50 psi heads and want 6 heads per zone (and need 5 zones) in order to cover the area you wish, you will need one of the above listed pumps. 2.5 X 6 = 15 GPM. A 10 or 12 GPM pump will not cut it. If you want to take a shower or make a pot of coffee at the same time, you need to make sure that you have adequate water to supply your household needs as well.
An image from Randy's website of one of his jobs
Of course, if you want a little more water than that, we can help you there, too!