Hi everyone, hope to be comeing out for good,( oh no not another one i here you say)

Been looking at the price of Septic tanks( yellow suba) although the price is not too bad, i'v been looking on the net and found it's not to hard to build  my own. Bloke built one out of 40gall plastic barrels.As we don't have any near neighbours, has anyone built their own, and got any tips. We live on a mountain side with lots of terrace :-/