over filling water cistern

[thegraywolf]

can someone please explain to me why over filling a concrete water cistern is a bad thing? pressure? or just the mess? would it not just over flow out of the hatch? thanks for the help.

[tool]

I have a cistern, about 12,000 litres. Definitely makes a mess in my basement when it overflows. Is yours buried in the ground or something?

I imagine excess water overflowing around it and saturating the soil would not be great as it could cause the cistern to sag or heave in wet soil damaging it or the attached plumbing?

In fact I’m waiting for a water tank to fill and haul to my cistern right now.

🙄

[thegraywolf]

ya sorry maybe i should have been more clear. mine is in fact buried outside my house. there was a thread on a local neighbours page about how a water hauling company damaged a cistern by over filling. just wondering if im missing something. i guess that would make sense that is could sag but what the hell does it do when it rains then? i dunno thanks for the reply though.

[Ddawg]

My cistern holds 4200 gals and is outside, it’s gets over filled a few times a year. We have never had an issue, other than wasting water on the lawn and trees. It’s a concrete poured in place tank.

We also have good drainage away from the tank.


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[tool]

Maybe if it was poorly vented and they are putting big time pressure to it with a big pump?? I don't know.

Seen it happen in sprayer tanks where it would bust the vented lid if you overflowed it.

[Abomb177]

I forget what load I'm on a few times a year and overfill our buried concrete cistern. No damage to report yet. Fingers crossed.

[nimrod]

Our cistern is 2000 gal and it's located inside, no worries if over filled, just grab the mop, Mop away the over fill, our tank is fibre glass has light to light up the tank easy to not over fill.

[nelsonob1]

Originally Posted by thegraywolf

ya sorry maybe i should have been more clear. mine is in fact buried outside my house. there was a thread on a local neighbours page about how a water hauling company damaged a cistern by over filling. just wondering if im missing something. i guess that would make sense that is could sag but what the hell does it do when it rains then? i dunno thanks for the reply though.

Yes it is bad. The ground will get saturated and you will have geotech issues. Better to have an overflow pipe that takes the outflow away

[tool]

Originally Posted by nelsonob1

Yes it is bad. The ground will get saturated and you will have geotech issues. Better to have an overflow pipe that takes the outflow away

True, many setups have a significant overflow pipe. 2"+ in case of such a situation.

[lannie]

The only way it would be a problem is if it was not vented or the house did not have good surface water or ground water management. I.E no weeping tile or leaking basement walls or poorly built wood foundations.