Our house is ~20 meter long with on one side over the whole length a gutter. On both ends, I've connected 200L rain tanks, that will collect any rain into these tanks if they aren't full. I've cut out ...

Rain gutters take a lot of abuse: rushing water during rainstorms, exposure to weather extremes, heavy loads of snow in the coldest climes, clogs of fallen leaves, and the general ravages of time.