Free water surface based constructed reed bed need to be much larger than their subsurface counterparts to achieve the same level of treatment as the surface of the wastewater is at or above the surface of the soil support media. These systems however, can promote superior ecological diversity and aesthetics. There is a scarcity of reliable long-term performance data relevant to Ireland and its climate for such systems, and reluctance exists amongst some local authorities to permit the use of reed bed as stand-alone secondary treatment syatem.