Handy bit of info to have for harvesting rain water

[opsec]

If you are going to harvest rain water then keep in mind that every 1 inch of rainfall on every 10 square feet of water catchment surface area will yield 6.23 gallons of water. If the catchment surface is at an angle such as a roof top would be, then you will have to do some triginometry to determine what the actual catchment surface area is.

[Lady Lilya]

If your house is 10' x 10', the roof should catch the same amount of water (except if the rain is coming down at an extreme angle that approaches parallel with your roof).

[Atash Hagmahani]

Laugh. Good thinking.

Catching rainwater off the roof is not uncommon here--actually it's nice to get it into a container and away from the house. A recent news article though claimed that it is technically illegal to do so--the runoff belongs to the state!

One of the easiest ways to get relatively clean water (especially if your roof is a fairly intact material).

[opsec]

If you are catching rain water off of your roof, then yes. For any other arrangement you either need to calculate that, or measure it's ground footprint.

[Chem Guy]

This is a very politically charged topic here in the arid West due to water rights as this story illustrates.  My advice if you do collect rainwater, don't make a big deal about it with the neighbors.

http://www.ksl.com/?nid=148&sid=4001252

Catching rain water is against the law
August 12th, 2008 @ 11:49pm
By John Hollenhorst
Who owns the rain? Not you, it turns out. You're actually breaking the law if you capture the rain falling on your roof and pour it on your flower bed! A prominent Utah car dealer found that out when he tried to do something good for the environment.

Rebecca Nelson captures rainwater in a barrel, and she pours it on her plants. "We can fill up a barrel in one rainstorm. And so it seems a waste to just let it fall into the gravel," she said.

Car dealer Mark Miller wanted to do pretty much the same thing on a bigger scale. He collects rainwater on the roof of his new building, stores it in a cistern and hopes to clean cars with it in a new, water-efficient car wash. But without a valid water right, state officials say he can't legally divert rainwater. "I was surprised. We thought it was our water," Miller said.

State officials say it's an old legal concept to protect people who do have water rights. Boyd Clayton, the deputy state engineer, said, "Obviously if you use the water upstream, it won't be there for the person to use it downstream."

"Utah's the second driest state in the nation. Our water laws ought to catch up with that," Miller says.

So what about the little guy, watering with rainwater at home? Will anybody do anything about that violation of the law? Clayton said, "If she really does that, then she ought to have a water right to do it." He added that they would not likely make an issue out of it, though, because they have "bigger fish to fry."

After months of discussion, city and state officials worked out a tentative compromise with the bigger fish, Mark Miller Toyota. Jeff Niermeyer, the Salt Lake City director of public utilities, said, "He would basically be using a Salt Lake City water right and diverting it under our name."

State officials say the Mark Miller agreement could become a blueprint for other rainwater projects. Homeowner projects, although technically illegal, are likely to stay off the state radar screen.

[Atash Hagmahani]

I agree, Chemguy. Our local newspapers pointed out that it is technically illegal here--although ubiquitously flouted and our own water utility promotes the practice!!

It is unlikely to get someone in trouble here (if nothing else, you could scream "selective enforcement" because rainbarrels are so common here), but discretion is the better part of valor.

Using greywater (water from non-sewage drainage) is even more controversial because of the tiny risk of contamination from coliform (sp?) bacteria (washing dirty diapers, and letting the water drain into the garden, essentially).