I have to say that the water regs are the one piece of building regs that I hate the most, but the AECB approach does not appear to answer my concerns. In fact it seems to move in the wrong direction; being more prescriptive.
Let me state my opinions. I do believe that reducing water usage is a good idea (I really don't want to have to think hard enough to have an opinion about whether it is necessary,but I'm happy to accept the point). And we should be reducing the energy consumed (That I do think is necessary).
However, current policy clearly doesn't agree. And as a person about to build a new house, I don't see why I should suffer more than my neighbours in old houses. So until water meters are mandatory for all houses, and we penalise utilities effectively for leaks and bad infrastructure, I really don't see why I should face any additional regulation.
Our previous house and our current one both have water meters, and we use less than the targets. With power showers, full size baths, unrestricted flow taps, 9-litre WCs. The whole point is that what matters is usage, not fittings. We don't take half hour showers until the hot water cylinder is empty. If it's yellow, let it mellow (within reason!); if it's brown, flush it down.
So let's have compulsory water meters everywhere. Let's have tariffs that provide 80 litres/day/person free of charge, another 40 litres at current rates, and anything more at ten times the current rate. Or some similar scheme.
And no rules at all about what fittings I have or how I use the water.
In other words, the building regulations are entirely the wrong forum for a debate about water usage.
JMHO. Thank you for listening.