Towards development of a standard methodology for testing field performance of residential greywater reuse systems: case study of a greywater reuse system installed in 22 homes in Southern Ontario (Canada)

Using shower wastewater to flush toilets decreases the potable water demand of residential buildings, reducing pressure on existing water supplies. ‘Off- the-shelf’ greywater reuse systems intended for single-family residential dwellings have recently become commercially available, but have variable field performance. A standard field testing methodology was developed and applied to a greywater reuse system installed in 22 homes in Southern Ontario. Performance was quantified by measuring the water balance, water quality, energy consumption, durability, maintenance requirements, installation process, economics and user satisfaction with the system. The tested system was found to save, on average, 40.9 litres per household per day, occasionally meet water quality guidelines and generally have less maintenance and durability issues than previous generations, resulting in satisfied users. However, due to low water rates and high capital costs, there is a need for government subsidization of these systems which will, ultimately, reduce pressure placed on centralized water infrastructure.