Our water supply issues here were more related to overuse rather than underrain. There was a big dip about 15 years ago, and I said to a doom-and-gloom guy at work that all the government had to do was triple the price of water to $1/kl and the problem would be fixed. But politically they couldn't do that; instead they introduced water restrictions. Fair enough. Ironically, two years later the price of water started shooting up, because they couldn't make money selling less of it due to the water restrictions. So we got the same result in the end, just took the scenic route.
After that, the reservoir water levels started going up again. The city's still growing, though, and the population is starting to catch up with the water supply, so... let's see what happens.
Something like 70% of the water supply in this state goes to agriculture, and some ludicrous proportion of that was (perhaps, still is) lost due to open and unsealed water channels, so we're lucky in that we still have some buffer to play with.