So far as I can tell, the Government’s WRTs are internal to its own operations, and I have no information about its current FTE consumption levels or whether the means exist (metering etc) to monitor and manage these.
The targets themselves appear to be very “soft”, in that we believe current FTE consumption in the workplace to be around 4.4m3 per annum, mainly accounted for by toilet-flushing. Some of the targets appear to be above this figure, whilst even the most demanding are only slightly below.
I do not know how Government intends to pursue its internal targets, but in existing buildings the options are limited, with “hippos” in toilet cisterns being the most cost-effective; in older Government buildings with old-fashioned toilet cisterns, this would be even more effective.
In new homes and buildings the options are far greater, with workplace mains-water consumption being capable of being reduced by more than 90% in any building using rainwater harvesting and with a roof/occupancy ratio of around 10m2/FTE; where the ratio is less than that, the savings are reduced correspondingly.