Under the existing legislation, municipalities with populations greater than 100,000 along with 11 categories of industry, including construction sites over 2.2ha, must seek discharge permits from EPA.

The new storm water Phase II rule extends the requirement to construction sites covering between 0.405ha and 2.2ha and municipalities with storm sewer systems in built-up areas serving populations of less than 100,000.

The new regulations will control the impact of storm water runoff by issuing discharge permits under the Clean Water Act. Permits will be issued for at least 110,000 additional construction sites and over 5,000 municipalities across the US. Facilities and sites will have three years and 90 days to obtain storm water permits.

Those seeking permits will be expected to focus on ‘best management practices’ when drawing up storm water runoff reduction plans. ‘Best management practices’ include filter fences, storm drain inlet protection, temporary mulching and seeding for construction sites, as well as public education programs, storm sewer inspections and local storm water ordinances for municipal programmes.

The rule includes permitting exemptions which are intended to encourage up to 70,000 industrial facilities to introduce storm water exposure protection measures such as storm resistant shelters.

The new rule is intended to reduce the costs of drinking water treatment as well as to improve the water quality of US rivers and coastal areas.

Under the expanded programme, sediment discharges from approximately 97.5 percent of the area under development across the US will be controlled through permits.

Storm water that runs off city streets, parking lots, construction sites and residential yards can carry sediment, oil, grease, toxic materials, pesticides, pathogens and other pollutants into the sewer system. From there, it is discharged – usually untreated – into local streams and waterways.

Storm water runoff can contaminate drinking and recreational waters and is a major source of beach and shellfish bed closures. Sediment from storm water runoff has been identified as the single largest cause of impaired water quality in rivers and the third largest cause of impaired water quality in lakes.

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