The increasing scarcity of water coupled with escalating cost of fresh water and its treatment has prompted industry to think of water conservation, reuse, and recycling. Incorporating advanced technologies such as reverse osmosis, nanofiltration, and so on, would result in reclamation and reuse of water and less environmental damage, but to what degree, and with what trade-offs? To answer these questions, this paper will present a number of life cycle assessments (LCA) on industrial and municipal wastewater systems, with a focus on short-term and/or long-term effects and/or benefits of reusing and recycling waters on economics (life cycle cost), energy, public health, environment, and water-ecology. Some streamlined LCA case studies will be presented on water reuse/recycling practices in pulp and paper, food processing, pharmaceutical, power generating industries, ultraviolet disinfection for wastewater reuse, agricultural and land applications of reclaimed water, and water augmentation to creeks and rivers during summer low flow .