About 35 years ago a colleague and I were working on a research/demonstration system consisting of a septic tank, pump tank and a series of trenches fed by dropboxes. A common system now, but at the time innovative. Each trench was fitted with inspection ports to monitor water levels in each trench when we periodically visited the site. Inside the house we installed a water meter to keep track of the amount of water used. The system was designed for a typical 3-bedroom house and an estimated sewage flow of 450 gpd.
After a few months we noticed something unexpected.
