Pipe dream...

So the most important feature of our watertank is of course the pipe's coming into the tank. Without these it wouldn't be much more then a simple concrete cave / wine cellar perhaps. We made 4 in coming drains and 2 overflow drains. We also added a floor drain for draining the entire tank if ever needed. We are using the special white pvc pipe which is suitable for potable water, the black plumbing pipe is not.

Overflow drains at exactly 92 cm height.

Our drain pipe, which is a 2 inch pipe with waterstop around it. We will add a tap on the outside somewhere when we are done.