Isn't that a good outcome? Water efficiency is a net good outcome for your city. Raising costs to recoup the deficit is ok with me, personally, if objectives like sustainability and efficiency were achieved.
It would have been nice if the reward for doing so was less cost, since that was one of the big marketing messages of the campaign.
Instead they opted to give us less for more - perhaps that was the intention all along.
Raising taxes on citizenry because they're using less resources == bad thing worthy of riots