According to Article 19a of the Urban Waste Water Disposal and Treatment Regulation, individual small urban waste water treatment plants may be implemented in agglomerations with a total load of less than 500 PE if it is found to be cost-effective. I would like to know whether the public service operator is obliged to take care (maintenance, operating costs) of such a MSWTP or whether the owner of the building where the MSWTP is installed takes care of it.