Our hunting cabin has a holding tank... No septic field... I believe it is 1200 gallons. We have an alarm that goes off when we reach 75%. The county is supposed to come out and inspect the system once a year and make sure we have an active pumping contract, but I doubt they do...
We have gray water(sinks, showers, etc) filter through gravel and into the ground, but the black water(toilets), are sent to the holding tank. Now granted, we don't live in our hunting cabin full time so we only have to have it pumped out once or twice a year... We have the rule that if it's brown flush it down and if it's yellow let it mellow. That saves some holding tank space. It's costs $295 to have it pumped out... If you lived in a house full time, with a family off 4, that could get quite costly! Interestingly enough, when my dad bought the place 5 years ago, the county inspector said the holding tank was only 1 of 4 in the whole county. He said it was grandfathered in before the Chesapeake Bay Act made them illegal.
