Résumé
Aim: To evaluate the operational performance of water efficiency products in order to report the actual-versus-potential impact on water demand. Study Design: The study monitored the volume of water used from taps situated in two male and two female washrooms in an office building. During a 21 week period, the tap flow rates were decreased, without occupants being informed, and water usage was recorded and analysed. Place and Duration of Study: The first floor of an office building located at the Building Research Establishment (BRE) site, in Garston near Watford, UK. The study took place from December 2012 to May 2013. Methodology: Flow regulators were installed in-line with the taps to reduce the flow rate. Using flow meters and data loggers, the water usage was recorded and analysed. Results: During the 21 week study, 6,217 events were recorded, where an event consisted of one or both taps being used in the same visit by a single user. The installation of the flow regulators failed to provide robust evidence that a reduction in water flow from taps equated to an increase in water efficiency. Conclusion: Evaluating the operational effectiveness of low cost water efficiency products is time consuming and expensive. The actual performance of flow regulators, which are low cost and simple to install, failed to achieve the expected gains in water efficiency.