I can't speak to Illinois laws, it does seem a bit restrictive, but you have to follow the local laws. It would seem reasonable to allow a homeowner to install the system but to require inspection before it could be used. The subject of water charges for yard usage has been discussed before, and it seems there are many ways it is handled by different authorities. In my area, the meter is read every two months. When water is being used for irrigation, the city uses the meter reading taken in the dead of winter as a base rate upon which the sewer charge is levied. That means in the summer, while I have to pay for the water I use, I do not pay sewage on the amount of water used above that base rate. It's still costly, but the water is clean and in good supply whenever I want it. My backflow preventer has to be re-certified annually by a licensed technician.