Stormwater pollution has become an increasingly important problem. Part of the difficulty in solving it is that it’s not obvious who should be responsible. Should cash-strapped municipalities be on the hook or should it be developers and others who own and maintain large properties with acres of impermeable surfaces? Often, the answer given by EPA and state regulators is that municipal separate stormwater sewer systems, or MS4s are responsible, but they have the authority – and sometimes the obligation – to impose appropriate requirements on property owners.… More