Holding Tank Concern

Discussion in 'Pumps and Tanks Well Forum & Blog' started by gmacpro, Sep 10, 2007.

  1. gmacpro

    gmacpro New Member

    Messages:
    10
    Location:
    Canada
    I have a holding tank that a drill well feeds water into. I have a pressure tank in the house but there is no pump with in the house to draw water from the holding tank. I assume there is a pump inside the holding tank that pushes water into the house as the pressure tank demands water.

    I dropped something in the holding tank the other day and upon trying to retrieve the item with a net I noticed the tank had a fair bit of silt/settlement on the bottom (about 1 to 2 inches only a guess as I couldn’t see the bottom). The tank is 2 years old and I’m wondering if I should drain the tank and clean out the crap? If so, I plan to disable both the drill well and pressure tank pumps electrically and draw the water out vertically from the holding tank. Doing this, will I have pumping issues due to air locks or any other issues that I haven’t considered when I turn back on power?

    Gordon
  2. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    I assume you mean you think there is a pressure pump in the cystern, not the pressure tank. That could be correct, if so, it would be a submersible pump that usually goes into a 4" well.

    bob...
  3. Gary Slusser

    Gary Slusser That's all folks!

    Yes a cistern has to be cleaned from time to time. Cleaning includes sanitizing the tank and disinfecting the water and plumbing throughout the house. Cleaning one usually proves to be a real character builder. Once done, usually no one wants to do it ever again.

    To drain the tank, you can run water at the house, like an outside faucet, not into a septic system. Just don't let the pump in the tank run out of water.
  4. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    Think where all of that silt would be if you didn't have a holding tank!

    Is the tank above ground so that you can drain water out of it without pumping? If so, you can get a siphon started and suction stuff off the bottom. If not, you may want to get a high flow/low head pump to siphon it out.

    Is there a manhole big enough to let you get inside the tank? I have been in many tanks with the standard manhole that is usually used in the large plastic tanks and I weigh more than 200 pounds.

    You MUST ventilate the tank BEFORE ENTERING and also while inside. You can put a fan (like a box fan) blowing in over half of the manhole, and let it exhaust out the other half of the manhole. You should always have a helper outside the tank whenever you are inside.

    You may need a "wet vac" to clean it up completely.

    After you clean it you should disinfect it with bleach and run that water to waste. Put in about 1 pint of unscented (cheapest) laundry bleach per 1000 gallons of water and run it to waste. Then add about 1 cup of bleach per 1000 gallons of water for the first use to disinfect the rest of the system.
  5. gmacpro

    gmacpro New Member

    Messages:
    10
    Location:
    Canada
    I like your sense of reality, I've been in that situation before... after completing something and never wanting to do it again.

    Regarding your point about "don't let the pump in the tank run out of water". Since I'm hoping to vacuum out the silt etc, is there a trick to keep water around the pump? What will be required to get that pump working again if the water is removed?

    Gordon
  6. gmacpro

    gmacpro New Member

    Messages:
    10
    Location:
    Canada
    Interesting point about that silt - I'd be much heavier.

    My holding tank is below ground so I'll have to pump out the water or lift it out.

    The tank is fairly large, very easy to get into. The tank is concrete and thanks for the points about ventilation and a helper, I guess it would be classified as a confined space.

    Do you see any problems with getting the pump in the tank going again after I vacuum the holding tank?

    Gordon
  7. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    What he meant by keeping the pump wet; was to keep it wet while pumping. If the pump is turned off you can safely drain the tank with no damage to the pump.


    bob...
  8. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    If you are in the tank with a pump you should make sure the pump is powered with a GFCI protected circuit. You don't want to become part of the circuit grounding a high voltage leakage current.

    And you will obviously not be operating a gasoline powered pump in the tank.
  9. gmacpro

    gmacpro New Member

    Messages:
    10
    Location:
    Canada
    All great points, however I'll be manually drawing the water out of the tank as I have all the time in the world. I will make use of the garden hoses to draw as much as I can via the submersible pump then lift the rest, then vac the residual stuff.

    Thanks all for the help and the confidence builder to tackle this job. Sounds like the Home Depot commerical - "You can do it, we can help" The "we" are you knowledgable people on this board.

    Gordon
  10. Gary Slusser

    Gary Slusser That's all folks!

    A sump pump, which have a bottom inlet, is a great way to drain the tank but.. you in the water in the tank with electric is not good. Rigged right you drop the pump in the tank with you above ground and with something like a mop, stirring up the sediment and washing it toward the pump should take a lot of it out with the water.

    Of course you'd have the power off to the submersible pump and the water to the house and water (power to the well pump) to this cistern shut off.

    You're welcome. Let us know how it goes.
  11. gmacpro

    gmacpro New Member

    Messages:
    10
    Location:
    Canada
    As requested, here’s a follow up….

    Got up at 8 am and turned off the drilled well pump
    Had coffee and other business
    Started both sprinklers at 9:00 am
    2.5 hours later the submergible pump started sucking air so power it was turned off
    6 inches of water was still in the tank
    Placed fan at entry and let run until lunch was finished
    After lunch, entered the tank and manually bailed water as my wife lifted bucket with rope over and over again
    After 1.5 hours, the water was less than ½ inch however the sediment (clay) was 1 to 2 inches thick
    Using a snow shovel and garden rake all the clay was broken up
    The clay was shovelled into the bucket with rope (¼ to ½ full due to the weight) so the wife could lift the clay out
    3 wheel barrels later, all the sediment and water was shovelled / vacuumed out
    The clay was like concrete
    Turned the drilled well pump on until the submergible was covered in water
    Turned on holding tank pump electrically and started a garden hose
    Water flowed – great – no issues
    Stopped the hose and let the tank fill
    Added bleach and after tank was full opened the garden hoses into the woods
    Stopped the hoses and let tank fill again – didn’t go right to the pump (6 inches of water, was at 18 inches)
    Turned the drilled well pump back on – had supper, bath (hot bath) – wife too
    Having a drink

    Thanks for all the help.

    Gordon
  12. Rancher

    Rancher Guest

    That's a lot of work for something that didn't need to be done...

    After all, that water used to be down the "drilled" well with all the clay and silt all around it.

    So unless it was getting sucked up in the submersible pump, it wasn't doing any harm, and you will probably get more silt so what was the point.

    Rancher
  13. Gary Slusser

    Gary Slusser That's all folks!

    If you think it didn't have to be done, how much could he have allowed to build up before he'd have to do it!

    And since you say it was a lot of work cleaning out what was built up in only 2 years, how long would it take if he waited like 5 or 10 years!

    And do you mistakenly think that bacteria doesn't live in and under sediment?

    I would have like hearing he mixed up a chlorine solution and sprayed it all over the inside of the tank and let it sit for 20 minutes and then flushed it with clean water from the well and then pumped out the water before filling the tank and adding enough bleach to the tank water to be able to smell it in the cold water in the house. Let that sit for 20-30 minutes and then flush it out of all fixtures.

    gmacpro, you might think about a backwashed turbidity filter on the well water just before the well water enters this cistern. Delivered price of roughly $800 on the high side. Depending on the size dictated by how many gallons you pump each pump run and how frequently on a daily basis, maybe $500.

    How do you control the well pump? That determines if you can use an automatic backwashed filter or a manual version.
  14. Rancher

    Rancher Guest

    For you bacteria lives everywhere... and if the tank was not open to the environment, then any bacteria that was under the sediment came from the well, or got in the tank by someone cleaning it out.

    Rancher
  15. Raucina

    Raucina Previous member

    Messages:
    515
    I would agree that a much longer cleaning interval is in order. A hard compacted clay would not seem to be an issue to the bacterial influence, if the tank is periodically chlorinated. What was on your shoes in the tank is a much bigger issue. I would also seal up the tank and install a 1 micron filter for the air intake-exhaust.

    Hydraulic excavators have huge oil tanks and they breathe just like water tanks. If they did not have make-up air filters, the pump would be dead in a month. Quite odd to me that we do not consider the air intake to a drinking water tank as a contaminant. I guess hydraulic pumps are more important than our guts.
  16. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    The air that gets into a tank via the vent is the same air that you breathe into your lungs. It contains bacteria, fungus, pollen, viruses, and anything else you can think of. You can put a filter on the vent if you have one but it is unlikely that the tank will be perfectly sealed.

    Underground tanks are susceptible to infiltration of surface waters which contain the highest concentration of stuff that falls to the ground from the waste orifices of animals.

    You can't keep such a tank free of contamination. A little chlorine once in a while will keep the stuff from multiplying and keep the water safe to drink. Use one cup of household bleach (the no additive kind) per 1000 gallons of water, tossed around the top of the water. Stir it up with a canoe paddle if you can.

    I would not install a non-pressurized potable water storage tank without an automatic disinfection system tied to the operation of the supply pump.
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