My take on a cistern

Discussion in 'Back to Basics' started by oil pan 4, Aug 26, 2016.


  1. arleigh

    arleigh Goophy monkey

    Still working on the solar distillery ,trying to make it function more automatic.
     
  2. oil pan 4

    oil pan 4 Monkey+++

    I was looking around and found that my area can expect about 20,000 gallons per year for a 2,000 square foot roof.
    Which isn't bad.
    Then you can get 5,000 gallons easy from a rain storm.

    Pumping water how much power does it take?
    A lot of people think if you have a well then you have unlimited free water. That's not the case where I live.

    Best case let's say I pump 20gpm with a super efficient irrigation pump into a holding tank which would require 200' of head, let's round that up to 100 psi.
    Then let's say the pump is only 70% efficient. So about 1.5hp of hydraulic horse power rounding up. But lets say the motor isn't real efficient and it needs 3hp of input power. Or 2.2kw.
    20,000 gallons of water at 20gpm would take 1,000 hours of pump time or 2.2Mwh or 2,200kwh.
    That's about as much power as a typical 2,500 square foot home with a families of 4 uses in a month.
    So for me 2.2 mega watt hours worth of water falls from the sky each year. Some years it could be a lot more, other years a lot less.
    If you have a deep well then rain water catchment has to be a key part of your plan if you ever want to go off grid.
    If I'm way off and only half right that's still 1 megawatt hour per year.
    This is worse case, it really shouldn't take more than 2hp to get 20gpm.
    So it should take at least 1Mwh but no more that 2 and a quarter mega watt hours to pump that much water.

    So yeah I think I am going to build this.

    For me a tank that holds 5,000 minimum to be able to catch what a typical rain storm can deliver. I figure if I build a 8 foot tall 12x12 foot box that will get me close to 7,000 gallons depending on how thick the walls are.
     
    Last edited: Aug 15, 2017
    Ganado likes this.
  3. arleigh

    arleigh Goophy monkey

    You may want to weight that much water, and figure on a better design then a box, more circular with 1/8"x2"stainless steel bands around it.
     
  4. oil pan 4

    oil pan 4 Monkey+++

    An under ground box seems to be pretty common.
     
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  5. Ganado

    Ganado Monkey+++

    i know the area you live in and a suggestion, do a two part cistern if you can, we have one on one of the ranches in that area, runs into one concrete tank that gets cleaned out once a year (under the guise of swimming when i was a kid) and the 2nd tank we let moss and greens grow in along with fish. this helps filter the big stuff out better and provides aswimming hole. a pipe about 3 ft from the top of the 1st tank spilled into the second tank which was used for drinking water. It did smell fishy if we let the fish multiply but it was a good cistern system that was pretty balance. Made with concrete.

    it lookded kind of like this only slighly bigger and ony 4 ft was above ground
    [​IMG]
     
  6. oil pan 4

    oil pan 4 Monkey+++

    Have to do something like that.
    Commercial made tanks are just too expensive. They cost between 50 cents to over $1 per gallon of size.
    I can try the local pre-cast place but doubt they will be much better.
     
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  7. arleigh

    arleigh Goophy monkey

    I use those caged plastic tanks for water 250 gallons or better.
     
    BTPost likes this.
  8. Witch Doctor 01

    Witch Doctor 01 Mojo Maker

    Double check those caged tanks as some have been used with toxic chemicals that will leech into the plastic....
     
  9. oil pan 4

    oil pan 4 Monkey+++

    I finally got a 1,600 gallon rain water collection tank from the agg auction for $125.
    It didn't smell like it's ever had chemicals in it.
    Going to use it for rain water collection and irrigation.
    After all this is NM and you live and die by water.
     
    Ganado likes this.
  10. oil pan 4

    oil pan 4 Monkey+++

    v8bY0D7.
     
    Gator 45/70 likes this.
  11. Ganado

    Ganado Monkey+++

    @arleigh did you ever get a solar still up and working?
     
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  12. DKR

    DKR Raconteur of the first stripe

    Massive rainwater harvesting system outside of Benson AZ. Even with 10 in of water a year, fills all of his family needs. Well done video.

     
  13. Ganado

    Ganado Monkey+++

    great video I would have put a shed over the tanks rather than covering the ground with tin. shading the poly tanks will increase their useful life (the sun in AZ is brutal on plastic)
     
  14. techsar

    techsar Monkey+++

    Big math error...it would only be 1000 minutes, so take 2200 kwh and divide that by 60...36.67 kwh
     
    oldman11 likes this.
  15. arleigh

    arleigh Goophy monkey

    On the solar distiller , I've done a few experiments ,but I've had other issue to deal with , LIFE..
     
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  16. DKR

    DKR Raconteur of the first stripe

    The fellow has a channel on UToob covering his homestead. Some folks talk about 'thinking of going off grid'
    this guy is living off grid. He and his wife have a business that can be dome from anywhere (web site development) and using a Cell based internet connection, do just that.
    They aren't total off the grid, they have/use/pay for County mandated trash pickup.

    I'll be interested in what they do when their first child comes along.

    Still the videos are well done and worth the time to watch.
     
    Ganado likes this.
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