Be sure to follow the rule before you head out.
Rule: You must post before you leave.
Given the context, this seems more evil than is probably intended.
There are laws about collection and storage of rainwater all over the world unrelated to genocide. Water falling from the sky is the source of aquifers, lakes, and rivers that are important for everyone.
It is useful to have lots of stupid laws. It makes people feel powerless and frustrated. It means the police can always find excuses to persecute you.
The technicalities of the individual laws are not important. It's the psychological effect of the whole body of laws on a people.
The US does the same thing. People need to push back. Hard.
Rainwater collection laws in the US are based on conservation and fair allocation of a scarce resource.
In places that don't have scarcity, you actually have the opposite issue, where drainage might be restricted or mandated to prevent issues from harming your neighbors.
I can't build a dam on my property because it might flood my neighbor. People in the southwest can't collect water at will because it might dry out their neighbors.