Life has been extremely busy lately (even before holidays started rolling into the picture) and that has kept me from posting. But the ideas have been churning, just waiting for an opportunity to emerge onto these pages.
One thing I have been spending a lot of time thinking about and discussing with various people is the viability of rainwater harvesting for domestic water supply in places like Tucson. I know of people doing it so clearly it's possible. But I've been wondering what it would take to bring it more into the mainstream and maybe even be viable as a water source for a small development - not just the individual lot scale.
One person I know of who relies on such a system in the Tucson area is in a location where municipal water service is not available and drilling a private well is unreliable. So rainwater probably was their best option. They also weren't overly concerned with the cost of the system - they had resources to cover that and because of their desire to live in a remote location any option for water supply was going to be costly. I suspect this type of situation is the primary motivator for going with rainwater as a water source.
This makes me concerned that greater use of rainwater harvesting would lead to increased sprawl - as people move to locations where previously they may not have been able to build because of the lack of a water supply. But I think the reality is that the people who would choose this type of water supply are the ones who are likely to move into remote areas regardless and harvesting gives them an option for water supply that doesn't rely on a non-renewable source - such as groundwater (under most circumstances).
I'm still putting these ideas together and plan to post on this topic over the next few weeks, where I will try to outline the feasibility of rainwater as a domestic water source and the types of changes I think would be necessary (i.e. regulatory) to permit greater use of this type of system.