ric: I'd like to thank you, too, for the information. I do have a question: what is a two-stage cistern? Two separate tanks? One tank with two compartments? Why? I think I'm about to learn something. Leaf guards don't work on our gutters; they have to be continuously cleaned to remove sediment which blows onto the roof from the large oaks which surround our house. That's why I'm using two sediment filters. I would have liked to put our tanks in the ground, too, but we have caliche filled with rocks. We would have to blast or use a rock saw and it just doesn't seem worth the effort and expense. I believe we can camouflage our tanks with cedar boards, tellises, bushes and vines so that they are invisible. The downspouts are something else. I've got one that runs past our office window and there just isn't much I can do about it. A couple that live on acreage a few miles from us hired a consultant to design and supervise the installation of a rainwater collection system. They have two 10,000 fiberglass tanks down a slope from their house and garage, with gravity feed from their gutters to the tanks. They then pump water from the tanks to a room in the garage where they seem to have every water-treatment device known to mankind, including ultraviolet light and magnets strapped to the pipe. They have a well but haven't used it in several years (according to them). They do not have any kind of filters at the gutters; their downspouts go directly down into the ground and buried pipes run down the slope to the tanks. There is a large fiberglass tank at the inlet of each tank, with screens and fiberglass mesh filters in each tank. In this system, the downspouts are no more obtrusive than traditional ones that dump the water on the lawn; however, they present a problem which I find objectionable. When leaves, twigs, etc. are not filtered out at the gutter, they tend to collect in the pipes in the ground and the water that emerges at the tanks is brown in color. Even though the water is treated later in several ways, I still don't like the idea of passing the water through decaying debris before it is stored in the tanks. The pipes could probably be blown out periodically, but there doesn't seem to be any provision for this so it wouldn't be easy. Also, the fiberglass tanks are not opaque and probably promote the growth of algae. They are pleased with their system and it more than accomodates the personal requirements of this couple, the irrigation of their plants and shrubs, and drinking water for a few head of livestock. Our cistern water will not be potable and we live over an acquifer that seems to have no shortage of water so we plan to use our well to provide water for the house. However, who can predict their situation ten or twenty years from now? I won't be surprised if I wind up cleaning gutters frequently, testing and treating water in the tanks, and maintaining a battery of treatment devices in what USED to be our wellhouse.
By the way, so many of the roof washers don't provide easy access for cleaning or have small acess hatches that make it difficult or impossible to do a thorough job of clearing and cleaning. Human nature being what it is, if it's too tedius to clean the diverters or the filters, it won't get done as often as is desirable. I agree with you that people seem to regard rainwater collection as something new and innovative. Good heavens, water storage in cisterns of one kind or another dates back thousands of years.