Is it fair to require individual homeowners to pay for their own sustainable drainage system (green roof, natural infiltration, rainwater basins), without any kind of contribution?
no, the state should definitely contribute with subsidies or similar.
no, there should be some kind of incentive; it could be a tax reduction.
yes, because otherwise the cost of dealing with the water coming from their house will be borne by the rest of society.
no. rudersdal municipality just the other day decided that homeowners who want to drain on their own land will receive money.
again, the way you ask the question is biased.
i am not sure i understand the question. but i think it is fair that the individual house owner pays for their own suds without paying further tax to the collective system.