Thanks for the explanation - that makes it all logical. This topic is becoming of greater importance to me as we may well be in a position to start building at our farm in the next year or two and things like a septic system will be the stuff I suspect we may begin looking at as part of the site prep. I know we just need to get the right folks out to look at the place and decide what sort of needs/options we have for this. At least we have city water, so that part of the equation isn't too bad.