irrigation using a cistern as supply

Discussion in 'Irrigation' started by RyanD, Nov 28, 2006.

  1. RyanD

    RyanD LawnSite Member
    Messages: 178

    Hey guys. Haven't done much in the way of irrigation before but I just bought this house with a 2 acre lawn. I was thinking of irrigating it and using the cistern to supply the water (ithe water is caught from the gutters on the house). I am guessing the cistern is approximately 5000 gallons. Would this work? And what should I be looking at spending for parts / supplies (ballpark)? I am sure there is lots of info I didn't provide. Let me know. Thanks.
  2. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    I've worked on a couple systems like this.

    Ideally you would want a submersible pump inside the cistern. I've maintained a system that uses a standard centrifugal pump about 30 feet from the cistern and its been problematic.

    5,000 gallons would take a while to deplete, but I wonder how fast it would refill in the summer?
  3. Hank Reardon

    Hank Reardon LawnSite Senior Member
    Messages: 599

    Check local codes. If it is hooked up to the house, you may (should) be required to have a backflow device installed. For instance, besides a double check valve assembly, our local code will not allow tapping into an existing underground cistern being used for potable. We have to install a new one, above ground.

    Two acres is a lot of property to irrigate. Like DW brought up, the recharge could be an issue.
  4. RyanD

    RyanD LawnSite Member
    Messages: 178

    That is what I was thinking too (submersible).

    It is not hooked up to the plumbing inside any longer.

    I'm not really looking to irrigate it as much as most people would. Just supplement when precipitation is lower. Replenishing the supply could be a problem, depending on how long we go between rains.
  5. jerryrwm

    jerryrwm LawnSite Bronze Member
    Messages: 1,274

    You can also use a centrifugal pump at the cistern if it is an elevated cistern or an above ground unit. It will have a flooded suction so any pressure you make with the pump is not lost on suction lift. As close to the cistern as possible to locate the pump.

    Hank is spot on if the cistern is used for domestic water. Check the codes.

    Jon is correct. 5000 gals will last a while. It takes 27154 gals to put an inch of water on an acre so your water requirements for two acres will be somewhere around 54000 gals for 1" of water. The cistern will have to refill about 10 times to get you all the water you need. If it is refilling due to rain that often chances are you won't need an irrigation system anyway.

    You might consider using the cistern and pump set up to water a garden or flower beds etc. Use it for a smaller requirement system.
  6. paolaken

    paolaken LawnSite Senior Member
    Messages: 699

    you know how the summers have been around these parts the last few years. very dry. just had 1" of rain last night, the most we've had in months and months.
  7. RyanD

    RyanD LawnSite Member
    Messages: 178

    Holy Crap;) I think I will just water the garden:eek:

    So... do people with 2 acres ever irrigate? I would have a water bill in the 1,000's! (By the way, I checked the math. You are right on. I never would have thought it was that much).
  8. Hank Reardon

    Hank Reardon LawnSite Senior Member
    Messages: 599

    My largest residential client irrigates 5 acres (over two are turf).
  9. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    And to think that unless your cistern is regularly recharged and/or you have a lot of rain during the growing season you'll pull all of it in a fairly short time.:)
  10. Ira

    Ira LawnSite Silver Member
    Messages: 2,375

    I just had my part of my three acre yard partially sodded with 2400 sqyds of Palisades Zoysia (a little less than 1/2 acre of the yard). The area that was sodded is covered by an irrigation system with water provided by a submersible well. Each zone puts out about 28 gallons per minute at about 50 psi. I calculated that if I were to try to put down 1" of water per week on the sod, I would have to run the irrigation system for a total of eight hours per week, assuming relatively equal precipitation from each zone. Good thing we usually get a lot of rain.


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