I think Howard brings up a valid and timely point about a septic system being a "greener" alternative to hooking up to sewer. However, a non-functioning system will also be "green" especially in the heat of summer! If you see a green streak running from the tank's location out into a field that's NOT a good thing!! They are supposed to "leach" into the ground not come up to the top!
Another "green" aspect is that the sludge generated by human waste, and with it the chemicals we put into our bodies, would be contained in the tank as the liquids actually "leach" into the field for dispersion. However, in Sonoma County, Greatest State of California, we have some archaic thinking regarding leading edge systems. The County folks rely either on large expansion fields, at least 100' from an existing well head (this could get problematic if you're on a smallish lot and your well is close by as is your neighbors!), and/or a "at-grade" septic system called a "Mound". This system is sand based and actually will evaporate rather than "leach" down. Waste is "metered" into the system to allow proper evaporation. The county would have an easement for the life of the system to make sure your not "metering" too much. Yes, they install, what else, a Meter to determine this. You also may have to have future expansion of the system. You may also install a "grey" water line which extends the useage of your system substantially. The "grey" water system is very simple and takes your sink,dishwasher,washing machine,shower, water into a box with gravel where it leaches also. Any "waste" lines get routed to the septic system tank.
I think those who say "run" from septics come from ignorance of the systems and how they function. In our County some areas "perc" like crazy and the systems last 30-50 years before installation of new lines. Other areas we KNOW you'll be hard pressed to get a "perc" which will allow a septic system. Your only recourse is to wait for sewer. Our County also allows emergency repairs for those who have no alternative for sewer hookup or big expansion fields. But every County is different. Some of the systems spoken here would NOT work in my County. A qualified "Country property specialist" will have on his approved vendor list a septic inspector who knows his/her stuff. I've used a retired "Sanitarian" who worked for the County for my inspections. He was fun, extremely knowledgeable about perc areas, expansion, type of systems, etc and gave a very good report. Also, best practices as a Realtor, requires you to ask your client at the time of sale if they have any desire to expand their home. If they do you'll need to direct them to the County to see if the existing system needs updating and if it CAN be done!
But if you wish to be "Green" and not load our sewer systems with more waste and the bi-product of our waster, toxic sludge, stay "Green" and keep the septic!