In the case of no access to the water main in the basement their are other options. If your water spicket coming out side is 3/4" the irrigation can be run off of that existing pipe. The system would have to be designed around that restriction, which would results in more zones than doing 1" pipe. Is their no way at all to get to the water main in the basement? Where is your meter? Is that beried behind the wall aswell?
Also with the sewer cost, have you checked into splitting the meter? Some cities will alow you to instal a second meter for the irrigation system and out door use. The original meter will then measure only the water used in the house and that going down the drain, the 2nd meter only measures the water used outside that does not go down the meter.
Why do people not respect us as they do other tradesmen? Because every Tom, Dick, and Harry doesn't think he can be a plumber or electrician!