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Thread: Drain plug not stopping ground water

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    Drain plug not stopping ground water

    All,

    I am trying to fill up my pool after an acid wash, but the drain plug is allowing ground water to pass through it. It is a horrible design. Here is a picture of the drain and the plug.
    Attachment 59665Attachment 59666

    You see, the plug is designed so that only the plastic threads are supposed to stop the ground water from coming back up. Huh?!?! What person approved such a design?!?! Someone that works on pools for a living told me that he uses 13 wraps of teflon on the top threads to stop the water. Well, I tried that, and sure, it slows the water down, but you can clearly see water seeping through. My 9 year old daughter told me to try wrapping rubber bands around the top threads. I thought that was a good idea, but I'm not sure how rubber bands will hold up over time.

    Does anybody have any ideas? Maybe I can buy a new plug (since I've tried multiple times to get this one to work, and the threads are certainly no longer pristine...besides, Home Depot sells them for 99 cents) and buy some RTV gasket compound of some sort, then goop it on the top threads and let it dry? I keep mentioning top threads because that will allow the bottom threads to catch and allow me to turn it a few rotations before the gasket makes contact.

    Again, for the life of me, I can't understand why someone would approve such a design to stop water from coming from the ground (or keeping 11K gallons of water from leaking). Any advice would be GREATLY appreciated.

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    I should be clear that the plug is merely nothing more than a plastic bolt/screw without a head. There is no lip or head to stop it from screwing down past the drain hole. Also, my pic of the drain has the plug installed. I've tried many times with teflon tape; no dice. I didn't take a pic of the drain's threads...they just abruptly stop and then I can feel small rocks below. So, I guess I could keep screwing the plug all the way down to the rocks - but there's not point in doing that. Why didn't they use a design that had a hard stop with a gasket?!?!?
    12,150 gallons; in-ground; cartridge filter; 1986; K-2006 kit

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    wjr75's Avatar
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    Re: Drain plug not stopping ground water

    Is that in a main drain in the bottom of your pool? If so you should have a hydrostatic valve in there instead of a plug. If this is the case you need to get water in there before your pool pops out of the ground. Once you have water in your pool with a hydrostatic vale the pressure of the water won't allow the ground water in your pool. I'm not an expert on this so hopefully you will get the experts to pipe in.
    Inground 22k gallon gunite 15x31 main pool, 15x7 wading pool/sunning deck, hot tub/with overflow (9' octagon with limestone top) & slide NSWG, Aqua Blue Pebble Sheen
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    Re: Drain plug not stopping ground water

    Since the plug is out, I'm not worried about the pool popping. The pool has been like this for a couple of weeks. I have a very specific problem: I need to somehow beef the plug up to stop the ground water.
    12,150 gallons; in-ground; cartridge filter; 1986; K-2006 kit

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    Richard320's Avatar
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    Re: Drain plug not stopping ground water

    Quote Originally Posted by kri5tian View Post
    Since the plug is out, I'm not worried about the pool popping. The pool has been like this for a couple of weeks. I have a very specific problem: I need to somehow beef the plug up to stop the ground water.
    If the port is designed for a hydrostatic valve, the valve itself may have longer, tapered threads or even a captive O-ring. I've never been down to mine, so I have no clue what they look like. Oops, now I do. I just did a google image search.

    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: Drain plug not stopping ground water

    You can use some teflon tape or teflon based pipe dope on the threads to help it seal better.
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    Re: Drain plug not stopping ground water

    Ok. I ended up ordering this part:
    Attachment 59679
    It is designed for 1.5" or 2" drains. My drain is 2". What annoys me is that there is no o-ring under the 2" lip...so how is it supposed to seal my drain? I guess I'll try lots of teflon tape again. But here's the BIG kicker: I DON'T WANT GROUND WATER IN MY POOL! The ground water smells a little like sewage, and I don't want my kid swimming in that. I guess I'll go out there and try to re-use the original plug...this time with 15 wraps of teflon tape. Woe is me.

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    Forgot to mention that the part I ordered is a hydrostatic valve, which is designed to allow ground water to come into the pool. I really don't want that. Sure, it supposedly prevents pool pops, but my water table is low right now...and I plan on filling it back up before it gets high again. How do I know my water table height?...because when I leave the plug out over night, the water only comes up to shin-deep.
    12,150 gallons; in-ground; cartridge filter; 1986; K-2006 kit

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    Re: Drain plug not stopping ground water

    If that is a hydrostatic valve ithe o ring is for the valve not the threads

    - - - Updated - - -

    If you ever get ANY water in your pool you want a hydrostatic valve. The o ring is for the valve not the threads.

    Any water in the pool means a high water table and water tables fluctuate up and down so if you have water you want the valve in case there is a situation where the table gets high enough long enough to float your pool. Think of it as a real cheap insurance policy.
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    Re: Drain plug not stopping ground water

    Once you get the pool full above the water table the pressure in the pool will be equal to or higher and the ground water and the hydro static valve will close at that point no more ground water will be coming in. Drain as much of the smelly water out you can and fill as fast as you can.
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    Re: Drain plug not stopping ground water

    But guys, if I use the valve, how do I know that the valve's threads will prevent water flow? Right now, my problem is that my normal drain plug leaks water. Since this valve does not have an o-ring where the threads end, how will I know it seals? The valve is designed so that water can flow through the interior valve, not the outer valve threads. Do you guys get what I am saying?

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    Also, this house was built in 1986. The water table in FL gets HIGH in the summertime, and the pool hasn't popped with using a regular plug and not a hydrostatic valve. But I hear you - a valve would be safer. I just want to make sure that the threads seal (and don't allow pool water to leak through to the ground).
    12,150 gallons; in-ground; cartridge filter; 1986; K-2006 kit

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    Re: Drain plug not stopping ground water

    I know what you're saying, and I think you'll need to wait until you have the relief valve in your hands to be sure one way or the other. The threads may be tapered where the plain plug isn't. Or there may be a groove for an O-ring but they left it off for the photo. It should become evident when you try installing it.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Drain plug not stopping ground water

    Thanks, Richard! I'm relieved that you understood! I think the only way I'll be able to tell is if there is a way for me to keep the valve closed while I install it. Otherwise, water will just be everywhere and I won't be able to see. Also, closing the valve would allow me to pump all the ground water out before filling the pool back up. Wow, I can't believe what a bad system/design this is!
    12,150 gallons; in-ground; cartridge filter; 1986; K-2006 kit

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    Re: Drain plug not stopping ground water

    The valve that Richard posted has an O-ring on it. A much better way to seal than a few wraps or Teflon tape. That's why I made sure to use the couplings with O-rings when I installed my new pump.

    I see your concern. How can you be sure you have a seal around the valve, if the valve stays open until the water level in the pool is higher than the groundwater? Well, I'm not sure you can, but you can be sure that once the pool is filled, any seepage would be out of the pool and never in. Groundwater can't enter unless and until you drain the pool to a level well below the ground water level again.

    But if it were mine, I would be searching for a hydrostatic valve with an O-ring seal.
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    Re: Drain plug not stopping ground water

    Thanks for the advice, chief. After a few puffs on my cigar, and a few sips of beer, I have decided to take the following actions. I will NOT use the hydrostatic valve. I will return it. Instead, I just used all of my remaining teflon tape to wrap the regular plug about 16 times. I will screw it in, and then use some water epoxy around the rim of it. This should plug the leak. Then, I will fill up the pool. Why am I doing this? Well, this pool is 30 years old and has not popped using a regular plug. Heck, chances are the plug never sealed correctly anyhow, and was always letting a little bit of water leak. This course of action will at least limit the amount of seapage. I'm not too afraid of the pool popping while my garden hose slowly fills it up, because the weigh of the concrete coupled with the relatively low water table (the water stops coming in about shin-deep) should save my skin. If I need to drain the pool again, I will drain it to shin deep in the winter (when there is a low water table, because it doesn't rain much in the winter) and then chip away the epoxy with a chisel. My oh my, what an ordeal this has been. I will never buy a house with a pool again until the technology catches up.
    12,150 gallons; in-ground; cartridge filter; 1986; K-2006 kit

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