GBZ39, go check it out. There is a holding tank behind the finished building. The system is an aerobic waste water treatment system. The solids go to the bottom, to be pumped out later and taken to the treatment plant. The liquids are treated, and eventually are clean enough to be used as gray water, to water gardens/lawns, etc. This same system is used in many parts of Texas and Louisianna and areas where conventional septic systems are not appropriate and town sewerage hook up isn't available. It's a pretty modern system, and one that many of the resorts/condos in the future will be using. My husband is very environmentally concerned. He went to visit the plant where this system is produced, and came away feeling pretty good about it. Eventually, the town sewerage will be available, but until then, this is the most environmentally friendly way to go.