A pump for greywater

GlennT · Sep 27, 2001

As so often in the past, I'm overwhelmed by the amount of information that comes out in this forum. Thanks so much. I've printed out the responses so I can refer back to them. By the way, I'm installing a rainwater collection system at the moment. We will have a 1,000 gallon ferrocement tank (actually a septic tank) at each end of the house and and two more 1,000 gallon tanks by two large garages (sheds) in different locations. We plan to monitor our usage of the rainwater from these tanks for a year or so and then have a large ferrocement tank built--probably with a capacity of 20,000 gallons or so. Our 1,000 gallon tanks will serve as catch basins and they will pump into the large tank. Thanks again for the information; it really is appreciated.

TerryinMD · Sep 27, 2001

What are you going to do with the stored water? We have homes in our area that still collect rain water for daily use. What they typically do is have a main collector that has a trap on it. When it begins to rain, you divert the water away from the storage system for the first few minutes of the rain. This water has most of the contaminents and dirt. Once the roof, gutters, and downspouts are "clean", you let the water drain into your storage tanks.

Terry

Bird · Sep 27, 2001

Glenn, how much rain do you get in a year? I don't think I'd get enough rain to fill those tanks in 10 years, even if I didn't use any in the meantime./w3tcompact/icons/laugh.gif

Bird

DocHeb · Sep 27, 2001

Good article in this months "Fine Homebuilding" (November 2001, #142) about using rainwater runoff for entire house water with no well or backup system. The author uses cisterns of 40,000 gal or more (water use for family of four for 10 months) and sediment filters with UV purification. It is an interesting article, but seems like a lot of effort. I think we're spoiled in the Great Lakes area since we don't think about our water supplies very often - maybe we should.

CGranat · Sep 27, 2001

My house covers about 3000 square feet of land (house, garage, and porch). Each inch of rain would yield 250 (=3000/12) cubic feet of water. There are about 7.5 gallons of water in one cubic foot so, this would be 1875 (=250*7.5) gallons! We get about 40 inches of precipitation here in Indianapolis each year. That makes 75,000 gallons in one year. I realize that this is the amount of water that falls; what you could collect and store may be considerably less. You got my curiosity up and I had to figure out what kind of numbers we’re talking about.
Chris

Chillimau · Sep 28, 2001

GlennT,

Check out the current issue of Fine Homebuilding. They have an article on rain water collection. Haven't had time to read it yet, but looks like they collect, filter and use the rainwater as drinking water.

Gary

Chillimau · Sep 28, 2001

Sorry about that, I just saw the other reference to Fine homebuilding.

What are anybody's experience with an aerobic septic system?

Bird · Sep 28, 2001

<font color=blue>What are anybody's experience with an aerobic septic system?</font color=blue>

Mine is about 4.5 years old now; only way to go as far as I'm concerned in this clay that does not perk well at all. There have been some minor changes in the design, but you can see basically what I have at http://www.hydro-action.com

Bird

GlennT · Sep 28, 2001

In our part of Texas (the Hill Country) we average a little over 30 inches per year (the local Chamber of Commerce claims 32+). We have 3,108 square feet of roof on the house, 1,080 square feet on a separate garage, and 1,280 square feet on a shed. Our house is L-shaped and part of the roof does not easily lend itself to rainwater collection (about 669 square feet). Figuring 4,400 square feet of metal roof suitable for rainwater collection and an annual average of 30.1 inches of rain, that should result in an annual total of 59,498 gallons of rainwater collected. This assumes an efficiency rate of 70%; in other words, 30% of this water is lost through roof washers, overflowing the gutters during a hard rain, etc. One inch of rain on one square foot of roof results in .6233 of a gallon of water. The formula to use is as follows: the number of square feet multiplied by the number of inches of rain multiplied by 600 (623.3 rounded off) and divided by 1,000. This figure is then multiplied by .70 to take into consideration the 30% loss. I plan to use roof washers on all roofs. According to sources I've consulted (the Internet and authorities at renewable energy workshops I've attended), rain washers should accomodate one gallon of water for every 100 square feet of roof. Much of this isn't high tech, but it sure takes a lot of time to locate information, make comparisons, and arrive at a reasonable design for a system.

Bird · Sep 28, 2001

Glenn, I hadn't done any calculations when I said that, and of course, I was just thinking of my little house, 1420 sq. ft. and not thinking about the shop, 2400 sq. ft., or the barn, maybe 1000 sq. ft. And our "average annual" rainfall is likely just a very little bit more than yours; the problem is that it all comes in the winter and early spring and not enough in the summer. I'm not sure exactly what the long term average is, but since I've kept track of it here at the house I do know that my average for the past 6 years has been 35.63". That's from a low of 20.7 in '99 to a high of 42.91 in '98 if you go just by the calendar year.

Bird