We have a quite heavy shower the other day and I was surprised to see lots of water running down the paved area next to the garage. I then noticed the water actually came from the water tank. And as shown below there's so much water that it over flows from the opening on the top!
I was actually not very convinced that this is what supposed to happen. As shown in photo below, the pipe marked with red arrows are supposed to be handling the overflowing water! Does this mean it's blocked, or the volume of incoming water is a lot more than the volume it can handle?
If you look this photo which shows the water coming from the gutter/down pipes above, I am not an expert, but this doesn't look like a lot of water to me.
Any way, I captured a short video as below, hopefully makes the whole thing more clearer to understand for everyone.
Any experts on this, any one? Do you think the pipe was blocked, or not designed/installed properly? Any other suggestions or opinions also welcomed!!