Rainwater Collection Tanks

Discussion in 'Homesteading Questions' started by YuccaFlatsRanch, Dec 11, 2004.

  1. YuccaFlatsRanch

    YuccaFlatsRanch Well-Known Member Supporter

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    Next week I will be going to place the order for the remainder of rainwater tanks I need to complete the system. I will order 2 more 3000 gallon tanks and seven 2500 gallon tanks that will fit under my big deck. It will give me a total storage capacity of 26,500 gallons.

    My system is such that I can gather 1400 gallons per inch of rain off of my garage roof and 3000 gallons per inch off of my house roof. Sounds like a LOT of storage, but when it rains here in Texas it usually rains a LOT at one time and to be effective you need to have the storage capacity to catch the rainwater. Its not unusual to get 3-4 inches at one time. That means I'd need to have available storage for 13,200 - 17,600 gallons to be truely effective and prevent wasting water. Even a 3/4 inch rainstorm means that I have to have 3,300 gallons of free storage.

    We average 32 inches of rain per year so in an average year I have the possibility of catching 142,000 gallons or an average of about 12,000 gallons per month.

    The conundrum is that in a normal rainfall year I need to only do minor irrigation of fruit trees and gardens, and don't need the storage. Assuming a half rainfall year at 6,000 gallons per month I can't do much irrigation even though that is when I need the water the most, and even the storage I have won't help much, but would keep the trees and gardens alive. What I really need is less tanks and a 50 by 50 by 10 ft deep pond to catch the overflow from the tanks. 25,000 cubic feet of water would be about 200,000 gallons, about 12 times the storage I will have.
     
  2. Brad

    Brad Active Member

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    What kind of tanks are you using? We're talking some dollars here aren't we.
     

  3. YuccaFlatsRanch

    YuccaFlatsRanch Well-Known Member Supporter

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    Above ground black poly tanks. Cost about $5,500.00, but cheap when you think about the cost of a well, and the rain falls on the house and garage roofs anyway - might just as well use it. Quality of the rainwater far exceeds the quality of the well water - slightly acidic and NO hardness. In addition I will disconnect from the local water system that costs me about $40.00 per month whether I use a drop or not and if I do use water it costs me $2.00 per thusand gallons on top of the $40.00 per month. Economic payback of the system about 7 years.
     
  4. edjewcollins

    edjewcollins Well-Known Member

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    What about using greywater for the fruit tree irrigation. Use a simple system like some I've seen that pipe grey water into a depression dug around the fruit trees that is filled with wood chips. Water helps break down the chips to provide nutrients. Chips keep everything covered and are porous enough to allow water to sink in while helping to stop evaporation. Chips also provide the media for the good bacteria that break down grey water before uptake by trees. As the chips break down and feed the trees you just add more! I know it's not a total solution if the gardes you mention are for consumption, but any ornamentals and the fruit trees should be okay and it's cheap to implement.

    Ed
     
  5. 3girls

    3girls Well-Known Member

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    Do you need a pump from the storage under the deck? Where do you order these? Are they hard bodied or more like a bladder?

    I am very interested in this. We get plenty of rainfall--this year required almost no watering. However, any water we use we pay for. If necessary, just post the link to earlier posts if you will. I'd appreciate it.
     
  6. ed/IL

    ed/IL Well-Known Member

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  7. insanity

    insanity Well-Known Member

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    My grandmother used to catch rain water in a cistern.(concrete square box in ground.Lots of old houses around here used them.)All the gutters in the back of the house went into a pipe in the ground and straight into the cistern.A well pump of some type pumped it back out.They must have paid someone to build it.As it was far smoother than any concrete work my grandfather ever did around the place.But the water was always really cold in summer,but no way for it to freeze in winter.The dimensions where some where around 20ft deep 12x18.Not sure how much water that is but as much as it rains around here it stayed full.I remember playing in the water as it boiled up out around the pipe from the gutters. :D


    If you have asphalt singles on your roof instead of tin.You might not want to collect it.Id suspect the oil run off would be bad in summer.
     
  8. YuccaFlatsRanch

    YuccaFlatsRanch Well-Known Member Supporter

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    The bible as far as I know it for rainwater harvesting is here:

    http://www.twdb.state.tx.us/publications/reports/RainHarv.pdf

    It will tell you all you need to know about what to do and as important - what not to do.

    My tanks are above ground black poly tanks that are connected together so they all fill at once. Yes I do have a pump and a well pressure tank to provide pressure to the water for use in the house. I treat with chlorine (bleach) and for drinking run the water through a reverse osmosis system. Its the BEST WATER I have ever had. Soap lasts forever, and no spots on anything.

    Our home is strawbale, our water is rainwater, we raise our own veggies, our own meat, and have our own orchards. We grind our own wheat and I am working on having enough land to raise our own hay and feed for the animals. Now if they could just perfect a fuel cell I could be "almost" totally independent from the world.
     
  9. mary,tx

    mary,tx Well-Known Member Supporter

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    I have a couple of questions about this...

    How does one filter the water of leaves, sticks, dust, and other debris?

    How does one prevent bad stuff, not just algae, but the single cell variety, from growing in the water that is stored for long periods of time in the summer?

    I know that it seems that rainwater in Texas has some sort of magic in it. You can water and water with a hose and only keep a garden alive, but when the rain comes, it really grows.

    Dale (DH of Mary, TX)
     
  10. YuccaFlatsRanch

    YuccaFlatsRanch Well-Known Member Supporter

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    There are numerous designs for "roof ashing" systems. Mine is integral to the 4 inch PVC pipe that fills the tanks from the gutters. On my system approx 50 gallons is automatically diverted from the tank prior to any water going into the tank. The debris goes in here.

    The tanks are black so algae does not grow. The bacteria and giardia etc are taken care of by the chlorine bleach added to the tank. My water has never had any growth of any kind in it, and the basic system has been in use for 4 years.

    There are several magic parts to rainwater. First it doesn't have all the salts disolved in it (read calcium etc here). Second when rain falls it picks up nitrogen from the air and causes plants to grow because of this element. After sitting for any length of time the nitrogen in solution evaporates though.

    I had a local retired nurse tell me I was going to get sick drinking rain water. I asked her where she thought her water came from. She said the river. I should have also asked her where meat came from, but I was slow on the uptake that day. I did explain that her water started out as rain and ran down the city streets and across farm fields etc before getting into the river. Mine just ran across a relatively clean metal roof. She still didn't believe me.
     
  11. BobK

    BobK Well-Known Member

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    YFR-is there a reason you are using reverse osmosis in the system? Why not use it direct after sterilization?
     
  12. YuccaFlatsRanch

    YuccaFlatsRanch Well-Known Member Supporter

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    Because I have the system already installed in the house water system, and I am too lazy to bypass it. I also have an activated charcoal prefilter to remove chlorine and .5 particulates.
     
  13. YuccaFlatsRanch

    YuccaFlatsRanch Well-Known Member Supporter

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    Did a water usage spreadsheet per the reference I cited and using 4500 gallons per month for the cool months and 7500 per month for the hot months and figuring 50th percentile year and a 25th percentile year (calculates out that 95% of years will be this amount of rain or greater based on historical) I will never run out of water at these usage rates, IF I start out the year with the tanks FULL.

    A month with 6 inches of rain will fill all of my tanks even if they are empty.