Constructed wetlands are artificially created systems that mimic natural wetlands’ function of purifying water. In this case, they treat household wastewater, or greywater, which, apart from a few contaminants, is relatively clean and capable of being reused. NOTE: We do not treat toilet water, or blackwater, as it is called. This system consists of several bathtubs filled with gravel, which have water plants growing inside them. Wastewater passing through the aerobic root zones of the plants is cleaned by the bacteria living there. The bacteria consume organic nutrients while the plants themselves uptake nitrogen and phosphorus. By the time it exists the system, the water has been made safe for reuse in irrigating vegetable crops. Plants used in this system include: bulrush, taro, cattail, papyrus, swamp hibiscus, canna lilly and phragmittes reeds.