Since the mid-1980s there has been increasing interest in constructed wetlands and their ability to provide a cost-effective, low-energy and robust means of water treatment. This state-of-the-art review details the benefits and limitations of constructed wetlands to treat domestic, agricultural and industrial wastewater, and urban and highway runoff. It also describes wetland operation, alternative design options, and management strategies, together with their economic and environmental considerations. It will be of interest to a wide range of users, including those concerned with engineering, environmental considerations, planning, regulation, consulting and research. The review contains an up-to-date presentation of the data currently available which can be used effectively by the knowledgeable practitioner. This mainly relates to England, Wales and Scotland, but is also applicable to the international community. Contains examples from 70 sites visited throughout the UK and an extensive reading list.