Chris Brooks has a post on proposed legislation in Arizona that would have created incentives for large-scale rainwater harvesting and groundwater recharge. The idea was to give people water rights to the resulting water stored in the aquifer.
As Chris notes, there are a couple of problems. First, some of the rainwater you harvest and store underground would have otherwise drained to a river. Where downstream users have water rights. This the classic conundrum that dogs our discussions of the issue here in New Mexico. It’s not free water, and just because it runs off of your city doesn’t mean it’s being “wasted”.
Chris raises a second, much more nuanced and interesting issue:
Looking at the original legislation, it seemed pretty silly to me that you would go to the expense of harvesting rainwater just to put it in the ground, then pump water back out of the ground to provide to customers. Seems a lot simpler to just spend that money buying rain barrels for people they could use to harvest their own water to then use in place of potable water. In theory, that would permit water providers in the area to reduce their pumpage, thereby cutting into the amount of the overdraft. But it doesn’t really work out that way. Having decisions made by thousands of individual homeowners is not how water providers like to manage their water supplies (although to some extent it is kind of like that now). And having current customers reduce usage doesn’t mean that water will stay in the ground, it will just be used somewhere else or at some other time. This also doesn’t create more renewable water that satisfies the requirements of state law, so it can’t help areas that need renewable water to keep growing.
In the end, the legislation went nowhere. Instead, they formed a commission to study the issue!