In mid-November, the Los Angeles Regional Water Quality Control Board issued a new National Pollutant Discharge Elimination System (NPDES) municipal separate storm sewer system (MS4) permit. The stormwater permit set total maximum daily loads (TMDL) for 33 pollutants and covers Los Angeles County and 84 cities within the Los Angeles County Flood Control District — an area spanning 7770 km2 (3000 mi2). The Los Angeles County Public Works Department is viewing this as an opportunity to manage water resources in a more holistic way and to protect water quality with green infrastructure.

However, the regulation does not guarantee compliance, because there are no penalties for plans that do not meet Clean Water Act standards, according to environmental groups. In addition, these groups claim that there has been slow progress in remedying water quality in waters previously listed as impaired. Some cities were also in opposition to the regulation, saying it would be too costly to improve stormwater controls over such large areas.