The general principle here is one from Economics 101 - free goods are used in very uneconomic ways. If water is unmetered, much is wasted since it's not even wo

The general principle here is one from Economics 101 - free goods are used in very uneconomic ways. If water is unmetered, much is wasted since it's not even worth thinking about whether you're wasting (literally) tons of water. Therefore even a very small charge for metered water (so small it doesn't cover the cost of providing that water) can change behavior remarkably, greatly reducing consumption and inconvenience to others. So even a charge of ten cents will discourage some trolls who would otherwise keep returning with a new free account after yet one more ban.