Underground springwater storage tank query.

[Steve shuff]

Hi All,
I,ve posted here as it seemed the most likely place, Admin please feel free to move if neccessary.

My home has a spring fed water supply and after filtering etc the water is piped into a 1200 litre (approx) underground tank.
Unfortunately a puncture has appeared right at the bottom of the tank and now we are losing around 200 liters in a 24 hour period.

The tank which measures 1000mm dia and 1700mm tall was put in around 40 years ago and has served us well,
This tank (fitted by the previous occupier) does not look to be a dedicated underground tank and I rather suspect it was made as a surface vessel.

My thought to remedy this would be to cut the top off the tank and line the base with sand and fit in a slightly smaller tank and fill in the cavity between the two with more sand.

The question is, would this be good parctice , or should I just dig the whole thing out and fit a more expencive dedicated underground tank ?
Thoughts and comments would be most welcome , Thanks guys/girls.

 

[jj4091]

Can you get specialised in-situ repairs done to that sort of thing.

 

[Elsa TLC]

I have no experience in this, but ill try to help you make sense.

First you don't want to contaminate the tank.

I would be inclined to fit a brand new purpose made tank beside the existing. Obviously if you have room . Then either disregard the old tank in the ground or remove so that it doesn't interfere with the new installation.

Trying to repair something that was never designed for that purpose, is more a sticking plaster on a wet finger.

 

[Steve shuff]

Thanks for the reply,
As I see it a repair would be out of the question, the hatch is so small only a child could fit through it, think that would be illegal . Also as the tank is 40 years old it may not be long before we get another puncture.
There is not enough room to fit another tank alongside, so ideally a drop in replacement seems the obvious answer albeit a slightly smaller one which would still suite our needs adequately.
I was trying to avoid the expense of a dedicated underground tank if a surface tank could be used instead. The underground tanks have strengening rings moulded into them to stop the walls deforming, but as we already have a tank in situ I wondered if fitting a slightly smaller tank in the old one and filling the cavity between the two with sand would give the new tank enough protection.

 

[Elsa TLC]

If it fits , and the plumbing is all accessible then why not.

Bare in mind I dont know much about these tanks. Id say as long you to contaminate. Then all should good.

 

[Scally-Ho]

Contact Enduramaxx for advice. I have one of theirs for RW storage

Enduramaxx Home

The UK's leading manufacturer of rotationally moulded water tanks (inc. potable) and liquid chemical storage containers. From 50L to 120,000L

enduramaxx.co.uk

 

[Old Salt]

That tank would be classed as a confined space and as such would need to be forced ventilated and tested before anyone could enter. Even a child although they are fine to be put up chimneys.

 

[aveatry]

I like the sound of your plan - cut the top off and put in a smaller tank but maybe fill the resulting void with polystyrene balls, and get away with a surface designed tank ? are they cheaper ? would 12 inch of sand or what ever would be the void fill have the same pressure as if it were in a new hole of its own ?
You me be frustrated bu finding the perfect size to fit so that you do not have to go too small.

 

[Harry Bloomfield]

would 12 inch of sand or what ever would be the void fill have the same pressure as if it were in a new hole of its own ?

I would expect the sand, over time, should the water level in the container reduce - to compress the sides of the new tank in. Polystyrene, might be too weak, and offer little support. However, mix a weak cement with the sand, and it would self-support. Drob the new tank in, fill with water, fill round the sides with the weak cement.

 

[JohnD]

Why do you want sand?

As a temporary expedient, some people use the large square plastic containers used for shipping fruit juice. I think they are 1 cubic metre, and very cheap.

When I had a well supply, it had an immersed pump, controlled by a float switch on a large loft tank. Would that do?

 

[JohnD]

My boating friend has what he calls a "bladder" which is a water container like a huge rubbery balloon that fits into a space in the hull. Somehow it was made to fit, but it collapses down when sucked dry. I don't know who makes them. He is not a biker.

 

[Steve shuff]

When I had a well supply, it had an immersed pump, controlled by a float switch on a large loft tank. Would that do?

Thats what my system does , a large loft tank with a pump and float switch, this pumps water from the leaking underground storage tank into the loft tank.