Rainwater is clean water that we can put to good use for our house and garden plants and to prevent dehydration. It is therefore unfortunate that much rainwater still disappears through the drainpipe into the sewer and mixes with polluted water. If your house or business premises are connected to the public mixed sewer system, you can disconnect your downspout from the sewer system. You can apply for a grant for this. Is it a newly built house or building? Then your building is probably already disconnected from the sewer system and you cannot get a subsidy.