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Thread: low flow/pressure from domestic well

  1. #1

    Default low flow/pressure from domestic well

    First,
    Thank you for offering this forum. It is great that there is a community available for us to find help/solutions to our problems.

    I am a first time domestic well user, having purchased this house a year ago, I don't have any experience with wells.

    My holding tank became water-logged a couple of weeks ago. I had a local company come out to fix it (so I could also watch and do it myself next time).
    They drained the tank, etc, but also installed a bleeder valve and back-flow protector at the well head.

    While they were there, I asked the tech about the pressure dropping below 20 pounds (even down to 10 pounds at times) when I run the sprinklers and fill the pool (running the water for a long period of time).

    He said that the pump should always keep a certain amount of pressure going regardless of the pressure gague on the holding tank, and that the only reason the flow should drop that low is if the water level dropped down to the pump.

    He said the pump could be wearing out and suggested that I may want to replace it before it fails.


    I did my own experimenting and found the following:

    I ran the water continuously and checked the level of the water in the well with a well water line tester (with the beep when it hits water). I also checked the depth of the well.

    The well is 156 feet deep and the water level never dropped below 26 feet even though the pressure in the holding tank dropped down to 20 lbs. I pulled the line a couple of times and wiped it dry just to be sure it wasn't picking up residue and beeping from that.

    After reading several posts on this site, my thoery is that the pump probably has a much lower flow/pumping capacity and once the holding tank drops to a certain level, I am getting just the flow from the pump. I still need to do a test to see what the pump is actually pumping per minute, but I wanted to see if anyone could verify that that is probably the issue.

    My only concern was that he said the pressure should never fall that low on the holding tank. I don't want to spend a ton of money on a new pump if I just need to adjust my sprinklers and just fill the pool with a 1/3 open hose valve instead of higher.

    Thanks for any feedback!
    David

  2. #2

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    You did not say if it ever gave higher pressure or is this something new. Being new to the house you donít have a history of performance to work with.

    From your research you have determined that your well is not pumping dry.

    What kind of pipe do you have from the pump to the tank? Thinking of a possible restriction.

    Have you pulled to pump to check the inlet screens? Again a possible restriction.

    What is the HP and age of the pump?

    The tech may be correct in that the time for a replacement is getting near.

    Just a few thoughts.

    Paul

  3. #3

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    Quote Originally Posted by PEW
    You did not say if it ever gave higher pressure or is this something new. Being new to the house you donít have a history of performance to work with.
    From your research you have determined that your well is not pumping dry.
    What kind of pipe do you have from the pump to the tank? Thinking of a possible restriction.
    Have you pulled to pump to check the inlet screens? Again a possible restriction.
    What is the HP and age of the pump?
    The tech may be correct in that the time for a replacement is getting near.
    Just a few thoughts.
    Paul
    Thanks for the reply. The holding tank kicks the pump on when it drops below 40 and stops at about 60-65.
    When they put the backflow protector in, I saw that the pipe in the well is galvanized. I would expect the pipe to the house is the same. I didn't pull the pump to check the inlet screens.
    Today, I set the hose to run about half blast and it ran all day without the holding tank pressure dropping below 35 (it pretty much maintained that pressure reading). I checked the water level after 8 hours and it was holding at 31-32 feet.

    I don't know its age at all, but if the drop in pressure could be based on demand (some insight here would be nice), then I think it may be the capacity of the well pump.

    I am trying something else now, I opened the valve all the way and am going to monitor the pressure and the water level.

    I will post what the pressure level drops to and if there is a decrease in flow and/or drop in water level in the well.

    Thanks,
    David

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
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    Default

    The galvanized pipes may be clogged up internally with rust scale. Not sure how easy it would be to test. A total flow rate compared with the rating of the pump may help. My unprofessional opinion.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  5. #5

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    I ran the hose at full pressure. It took an hour for the holding tank pressure to drop to 20 pounds.

    Once it got down to 20 pounds, I checked the water level in the well (it was still high registering a little higher than earlier).
    I then timed filling a 5 gallon bucket and I got a little more than 4.5 gallons in one minute. The flow from the hose was noticably lower than when I started it running it with the valve wide open (after running it all day maintaining 37 pounds on the pressure gage). I didn't check how many gallons in a minute when I started (Dang! I'm doing things backwards). But will check later.

    Any thoughts ae apreciated.

  6. #6

    Default

    Okay,
    I turned off the hose for about 15 minutes and let the tank build up pressure to 40 pounds, then I opened it all the way again (dropped down to 37) and then tested the flow.

    I got 8.4 gallons in one minute.

    So.....I have no idea what all this is telling me.

    Any ideas?

  7. #7

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    My guess, and only a guess would be the pipe or the pump. Depending on the age of the pipe, and the condition of the water, you could well be looking at restricted capacity.

    Paul

  8. #8
    That's all folks! Gary Slusser's Avatar
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    How are you measuring the water level in the well?

    Here's how things go. The well has water stored in it until you use water and the pump runs. The pressure switch causes the pump to come on, not the tank. When you run alot of water, the water evel in the well will fall unless the recovery rate of the well is equal to or higher than the gpm you are removing from the well. The lower the water falls in the well, the harder it is for the pump to move water and depending on how the pump was sized, the pump may get to a point where it can not move any water although there may be x0' of water above the pump.

    I think you need a pump guy (under Wells or Pumps in the yellow pages) or well driller or only a plumber that is capable of pulling the pump, to do electrical tests to see if the pump is operating electrically as it should.

    Gary
    Quality Water Associates

  9. #9

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    Thanks Gary,

    I may end up doing that, but I have a hunch that it is a hole in the pipe.
    I think I figured uot a way to test it.
    What I think *may* be happening is once the water level falls to a certain level, the water is escaping from the pipe and just keeps getting recirculated, and i'm only getting the amount of water that is recovering above that level.

    I think that my previous water level tests may have been bad (I was testing the level while the pump was running) and the sensor may have been hitting a pipe leak, not the water level (I only have the 1/2 inch hole to drop the line down so it will pretty much always fall into the same area of the well casing).

    Either way, since I only have this problem when running water at full blast for about an hour, its only a problem when I fill the pool (or run the sprinklers, but I can work around that), replacing the galvanized pipes (and pump since its probably 15-20 years old) would probably be in order.

    At least I should start saving now before i'm out of water and have to use a credit card!!!
    I will post the results of my test tonight (I've run the pressure down to 20 pounds with the flow rating slowing, and once the pump stops pumping, I'll see if the level in the well is suntantially lower than my previous readings).
    D

  10. #10

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    Just for my last test. After letting the pressure/flwo run low, and after letting the pump fill the tank about 10-15 minutes), I checked the depth of the water in the well.

    It was far lower than my previous readings (88 feet), but the high has been about 32 feet (I had a 26 foot reading, but I think that was false).

    After an hour, the level was back up to 32 feet. Since the well is 156 feet deep, I think it is either the pump not able to pump once the water gets much lower, or there is a hole (or multiple holes) in the pipe that finally cause the actual output from the well to decrease to the low of 4-5 gallons per minute.

    I never get sand or sediment in the water so I don't think it is bottoming out and filling up to the 88 feet level in 15 minutes.

    Does this sound like a pretty good 'diagnosis'? Thanks,
    David

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