we are putting together a bid for 4 Ruby Tuesday restaurant locations. the current company subcontracts an irrigation company to come and purge the system for winter prep. my question is what is a common price for something like that. the system wont be much larger than a medium to large sized residential system b/c of the limited area of grass. i can get my uncle to help out as he has installed multiple systems before. would a 20 gallon compressor be enough to purge? ive seen companies rent large tow behind compressors for residential systems.