Underground Cistern

[midrover170]

Hi folks -

Finding myself in a bit of predicament. I'm going to have septic installed in the next 3-4 weeks and would like to get my cistern placed at the same time. Living in Idaho, I thought finding water tanks locally would be no problem at all. Unfortunately, I'm unable to find the one I want: a 500 gallon spherical cistern for underground use (Norwesco makes one). This tank is ideal because it stays put underground, even if empty. If I want the spherical tank, I'm stuck ordering it and paying through the nose for shipping.

A local outfit makes the tank shown below, and it's designed for underground use. My lot has sandy/silty soils and is nowhere near the water table. Anyone have experience with a similar style tank, or have any recommendations on its ability to stay put if dry inside? I don't plan to have a dry cistern, but I don't want to regret it if that were to happen. The other problem with the local tank is that they don't make a riser for it. I'd have to set wide metal or plastic pipe around the manhole so that I could gain access. Not ideal.

Thanks.

[Redoverfarm]

Like a lot of things in life if we want something which we feel will be the best sometime you just have to bite the bullet and pay what they want.  Have you researched surrounding dealers to see what they can do.  Even if it requires a "day trip" to travel to pick it up that might be cheaper.  The tank does not weigh much and a small trailer should have no problem hauling it.  I see they have a dealership in Burley ID.  Don't know how close that is to you.

As far as the one shown would probably work but there is always a chance that it will not do what you want regarding lifting when empty.  Another problem unless you have a way to seal off the lid is seepage into the tank from ground water.  A 22" hole is rather large and you might have problems finding something to mate up to it.

[MountainDon]

If you have a manhole extension that breaks the surface that creates a path for the cold to drop through to the water in the tank. We had trouble with the exposed manhole extension permitting the top of the water in the spherical tank from freezing. That was resolved by building an insulated box that covered the manhole extension.  So burying the tank with no manhole extension may be the better idea. As long as you know where the cover is located then it can be reached by excavating. .... At least that was our experience.

[midrover170]

If you have a manhole extension that breaks the surface that creates a path for the cold to drop through to the water in the tank. We had trouble with the exposed manhole extension permitting the top of the water in the spherical tank from freezing. That was resolved by building an insulated box that covered the manhole extension.  So burying the tank with no manhole extension may be the better idea. As long as you know where the cover is located then it can be reached by excavating. .... At least that was our experience.

Hi Don. Thanks for the tip. What size tank did you go with? 550 sounds good, but if I can get by with 325, I save A LOT. It's a weekend cabin for three people.

Thanks.

[MountainDon]

The 325.  It serves us well but then we are very conscious of use, and don't have things like washing machines or flush toilets to operate.

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