United States Office of Water EPA-833-F-99-020
Environmental Protection Washington, DC 20460 October 1999
Agency www.epa.gov/water
REDUCING POLLUTED RUNOFF:
THE STORM WATER PHASE II RULE
As part of the Administration's ongoing efforts to curb polluted runoff, the Environmental
Protection Agency (EPA) is finalizing a new rule to control storm water runoff from smaller
storm sewer systems in urbanized areas and smaller construction sites. The second half of
EPA's effort to control storm water, the storm water Phase II rule will make approximately
3,000 more miles of rivers safe for boating and protect up to 500,000 people a year from
illness due to swimming in contaminated waters. Improving controls on storm water runoff
will also prevent thousands of annual beach closures, make fish and seafood safer to eat, and
reduce the costs of drinking water treatment.
Storm water runoff is polluting our waterways. When it rains or snows, the water that runs
off of city streets, parking lots, and construction sites can wash sediment, oil, grease, toxics,
pathogens, and other pollutants into nearby storm drains. Once this pollution has entered the
sewer system, it is discharged-untreated-into local streams and waterways. Known as storm
water runoff, this pollution is a leading threat to public health and the environment today.
Improving controls on storm water runoff. New regulations being finalized by EPA, known
as storm water Phase II, will reduce the impacts of storm water runoff through a strengthened,
yet flexible and cost-effective, storm water program. Phase I of the storm water program,
which was promulgated in November 1990, covered municipal storm sewer systems serving
populations over 100,000, construction sites above five acres, and industrial activities.
Expanding permit requirements for municipal storm sewer systems. Building upon the
existing storm water program, storm water Phase II requires municipal storm sewer
systems serving populations under 100,000 that are located in urbanized areas to obtain
a National Pollution Discharge Elimination System (NPDES) permit under the Clean
Water Act. This will result in storm water controls for approximately 5,040 additional
municipalities across the country. Types of controls could include public education
programs, storm sewer inspections for illegal connections, and ordinances to control
construction site runoff.
Providing flexibility for municipalities. The Phase II rule takes a "best management
practice" approach, providing municipalities with the flexibility to decide what these
practices should be. Municipal Phase II storm water programs are to be composed of
six minimum control measures, including:
public education and outreach;
public involvement and participation;
illicit discharge detection and elimination;
construction site storm water runoff control;
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• post-construction storm water management; and
• pollution prevention, or "good housekeeping," for municipal operations.
Municipalities may be able to use existing programs to satisfy these control measures,
thereby avoiding program duplication. The use of general, rather than individual,
permits is encouraged. There is permitting flexibility for municipal storm sewer
systems serving under 10,000 people, including waivers and permit phase-in options.
In addition, to control environmental and public health impacts, unregulated facilities
and activities that are causing water quality impairments may be brought into the
program and required to obtain a storm water permit on a case-by-case basis.
Controlling impacts of development. Storm water Phase II requires operators of
construction sites disturbing one to five acres to obtain an NPDES permit. Sediment,
which runs off of construction sites at a rate of anywhere between 20 and 150
tons/acre/year, 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. The additional
coverage provided under the storm water Phase II rule will ensure that sediment
discharges from more than 97 percent of the land disturbed by construction activity will
be controlled under a storm water permit. Types of controls could include filter fences,
storm drain inlet protections, and temporary mulching and seeding of exposed land
areas.
Providing incentives for industrial facilities. For those industrial facilities currently
covered under Phase I of the storm water program, the new rule provides incentives to
protect operations from storm water exposure. At least 70,000 industrial facilities may
be able to take advantage of this new provision by adopting practices to protect their
operations from exposure to storm water impacts, such as covering operations under a
storm resistant shelter.
Targeting polluted runoff-an Administration priority. The new storm water Phase II rule is a
key action under the Administration's Clean Water Action Plan. A primary goal of the Clean
Water Action Plan is to strengthen controls for polluted runoff, the leading remaining cause of
water pollution today.
The storm water Phase II rule was proposed by EPA in January 1998 and received more than
500 comments during a 90 day comment period. EPA will provide a 'tool box ' to facilitate
implementation, including fact sheets, federal financing programs, guidance, training,
research and additional support. Municipalities and construction sites will have up to three
years and 90 days from the date the new rule takes affect to obtain a storm water permit. For
more information on storm water Phase II, please call (202) 260-5816, e-mail your questions
to sw2@epa.gov or visit EPA 's website at http://www. epa. sov/owm/sw/phase2 on the Internet.
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