The reed bed system cleans up the outflow from septic tanks by supporting a highly active eco-system. The roots of reed mace (bulrush) & common reed supply oxygen to bacteria in the water, which digest the pathogens in the sewage. The lake water into which the reed bed flows (17) has been tested independently and shown to meet bathing water standards. It also looks good, supplies nutrient-rich water to the lake (and fish) and the waterfowl love it!