Comparative life-cycle assessment of ordinary and water-saving taps

The replacement of plumbing fixtures is a regular practice in the implementation of water conservation programmes in existing buildings. However, even though such programmes aim at reducing water consumption, it is necessary to understand the environmental implications of the replacement of ordinary plumbing fixtures with water-saving versions. The feasibility of such a practice, in terms of environmental aspects, should be evaluated in order to verify its effectiveness. This paper describes the application of a methodology to evaluate the environmental impacts involved in the replacement of ordinary taps with water-saving ones based on life-cycle assessment. The method quantifies inputs and outputs in the production, use, and disposal phases of the plumbing fixtures under analysis. The impact categories considered are global warming potential, depletion of the ozone layer, human toxicity, acidification, water consumption, and energy consumption. In order to assess the economic impacts, Life Cycle Cost methodology was applied. The method was applied in a water conservation programme of a university campus in Southern Brazil. The results indicate that the use phase of both ordinary and water-saving taps present strong influence in four impact categories (global warming potential, depletion of the ozone layer, water consumption, and energy consumption). Life Cycle Cost was estimated as R$245.99 and R$316.20 for the ordinary and water-saving taps, respectively. Such results show that the adoption of water-saving taps is not economically feasible without incentives from the public sector. On the other hand, the environmental performance of the water-saving tap was superior for all environmental impact categories analysed herein. The results indicate that the replacement of ordinary taps with water-saving taps would reduce water consumption by 26.2%, energy consumption by 13.6%, human toxicity by 4.6%, acidification by 0.2%, global warming potential by 14.8% and depletion of the ozone layer by 15.8%. Although the replacement of ordinary taps is not economically feasible, the use of water-saving taps is recommended on the campus where the study was conducted based on the environmental impacts in the life cycle.