http://www.techstreet.com/standards/ACI/350_06?product_id=1512045

Since we have no way of knowing where the H**L you are, check with the local city/county/state or whatever they call it where you are. Is this DIY?

Check the internet.

With the time, money and effort involved building a concrete tank, it might be easier to buy a polyethylene tank and just bury it, no cracking, crumbling and it would last forever.

Just for reference I have very recent quote for 5000 gallon cylindrical plastic (some kind of polyethylene) water tanks specifically built for domestic water storage at just about US$2000 each plus sales tax in California USA. These tanks are designed for above ground application and if any part is buried it needs to be protected from lateral soil loads by load bearing retaining walls. Such tanks in our area have largely replaced wooden tanks as well as steel tanks coated inside with a special "asphalt" coating approved specifically for domestic water tanks. The same dealer has underground tanks made to a different design in the 1000 gallon range for direct burial applications in septic tank systems.

Ed Weldon

Refer IS 3370 code to design tanks.

What is 3370 code : It may be a USA code We are in canda

This link will work in Canada too

ACI350