Uh, why? We already meter usage, so apply the tiered rates the same way we tier electricity.

Are you making a joke? The tiered water system would be implemented on the billing and invoicing side of things, not two separate water delivery mechanisms.

Huh? Why don't you just say tier 1 is n litres per day (enough for a large family to drink, cook, and wash. After that the price rises by x%.