The Vermont Agency of Natural Resources has revised onsite rules to allow constructed wetlands, subsurface drip distribution systems and smaller onsite systems. Previously, design flows for single-family homes had to accommodate at least three bedrooms. The design requirement is now a minimum of two bedrooms. The rules also waive the replacement drainfield requirement if the primary system handles 150 percent of the design flow and uses pressure distribution. Mound systems also do not require a replacement area if sized for 100 percent of the design flow. The previous rules did not mention composting toilets, although they have been allowed for
