United States
                       Environmental Protection
                       Office of Water
                       Washington, D.C.
EPA 832-F-99-024
September 1999
Storm  Water
Management Fact Sheet
Storm Water Contamination Assessment

A Storm Water Contamination Assessment (SWC A)
reviews a facility and/or a site to find materials or
practices that may contaminate storm water. This
assessment helps target the most important pollutant
sources for correction or prevention.

A SWCA program is closely related to other BMPs,
such as  materials  inventory,  non-storm water
discharges, record keeping, and visual inspections.


An SWCA program is applicable to any industrial
facility which contains areas, activities, or materials
which may contribute  pollutants to storm water
runoff from the total site. An assessment for storm
water purposes may also be applicable in situations
where a formal site assessment for hazardous waste
purposes is being performed.


A comprehensive SWCA program can eliminate
pollution sources that can impair receiving water
quality. However, there are limitations  associated
with  a   contamination  assessment  program,

     Assessments  need to  be  performed by
      qualified personnel.

     Assessments  are useful only  if there is
      corporate commitment to  reduce  any
      contamination sources discovered.

     Assessments  need  to  be  periodically
                     KEY PROGRAM COMPONENTS

                     A SWCA program should include:

                          Assessing potential pollutant sources and
                           associated  high risk  activities such as
                           loading and unloading operations, outdoor
                           storage activities, outdoor manufacturing or
                           processing activities, dust- or particulate-
                           generating activities, and on-site waste
                           disposal practices.

                          Determining which of these sources pose the
                           greatest risks of polluting  storm water
                           runoff from the site.

                          Selecting other  cost-effective  BMPs to
                           prevent or control pollution from the high-
                           risk sources at the site.


                     In addition to identifying problems within the storm
                     sewer system, it is even more important to prevent
                     problems from developing at all, and to provide an
                     environment  in which future problems can be
                     avoided. Thus, an effective storm water assessment
                     program  should   include  follow-up  activities

                          Educating   the   public   about  the
                           consequences of misusing storm sewers.

                          Pretreating  industrial  storm  water  or
                           disconnecting  commercial and industrial
                           storm water entries into the storm drainage

                          Tackling the problem of widespread septic
                           system failure.

      Disconnecting  direct  sanitary sewerage
       connections from the storm sewer system.

      Rehabilitating storm or sanitary sewers to
       abate infiltration by contaminated water.

      Developing zoning and other ordinances.

In some  communities that  are assumed  to have
separate  sanitary  and storm sewer systems,  the
storm sewer system may actually act as a combined
sewer system.  In these cases, the community may
consider  designating the  storm  sewer system a
combined sewer and treating the discharge.

A SWCA  program  and  the related correction
program need to be periodically updated, based on
their effectiveness and on the introduction of new
raw materials or changes in processes at the site.

Because the results and performance of a SWCA
program  depend  on the  severity  of the risks
uncovered and the corrective  actions taken, it is
difficult to quantify the water quality benefits of a
risk  assessment program.   Clearly, however, a
program that identifies potential pollution sources
and corrects them will improve water quality.

3      U.S.  EPA, Pre-print,  1992.  Storm Water
       Management  for  Industrial Activities:
       Developing Pollution Prevention Plans and
       Best Management Practices.  EPA 832-R-


Center for Watershed Protection
Tom Schueler
8391 Main Street
Ellicott City, MD  21043

Northern Virginia Planning District Commission
David Bulova
7535 Little River Turnpike, Suite 100
Annandale, VA 22003

Oklahoma Department of Environmental Quality
Don Mooney
Water Quality Division, Storm Water Unit
P.O. Box 1677
Oklahoma City, OK 73101-1677

Southeastern  Wisconsin  Regional  Planning
Bob Biebel
916 N. East Avenue, P.O. Box 1607
Waukesha, WI 53187
Costs for the initial  assessment  may  be high.
However, by pinpointing high risk areas, a risk
assessment may reduce overall costs associated with
a complete BMP  implementation  program.  The
costs associated with a risk assessment program for
storm water are small when compared with those of
an overall hazardous waste site assessment.


1.     Pitt, R., D. Barbe, D. Adrian, and R. Field,
       1992.  Investigation  of  Inappropriate
      Pollutant  Entries into Storm  Drainage
      System -  A  User's  Guide,  U.S. EPA,
      Edison, New Jersey.

2.     U.S.   EPA,    1981.     NPDESBest
      Management  Practices   Guidance
United States Postal Service
Charles Vidich
6 Griffin Road North
Windsor, CT 06006-7030

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for the use by the U.S. Environmental Protection

             For more information contact:

             Municipal Technology Branch
             U.S. EPA
             Mail Code 4204
             401 M St., S.W.
             Washington, D.C., 20460
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