Sewer Overflows Still Pose Health and
Kansas City infoZine
Published August 27, 2004
In a comprehensive report to Congress, EPA finds that
further control of sewer overflows is vital to reducing
risks to public health and protecting the environment
from water pollution.
Washington, D.C. - EPA concludes that adequate funding,
integrated local and regional watershed protection programs,
improved water quality monitoring and reporting, and stronger
partnerships among all levels of government, industry,
and citizens will be needed to make further progress.
Report to Congress: Impacts and Control of CSOs and SSOs
focuses on two types of discharges from municipal wastewater
systems - combined sewer overflows (CSOs) and sanitary
sewer overflows (SSOs) - and summarizes what is known
about the characteristics of CSOs and SSOs, the human
health and environmental impacts of CSOs and SSOs, and
the resources spent and technologies used by municipalities
to reduce the impacts of CSOs and SSOs.
Since passage of the Clean Water Act in 1972, EPA, states
and local water pollution control agencies have undertaken
numerous actions and initiatives to reduce CSOs and SSOs.
A combination of regulations, standards, federal funding,
technical guidance and policies are currently in place.
In April 1994, EPA issued the CSO Control Policy - a national
strategy to achieve cost-effective CSO controls that meet
health and environmental objectives and requirements.
Under the Clean Water Act, SSOs that reach waters of the
United States are prohibited unless authorized by federal
or state permitting authorities. SSOs, including those
that do not reach waters of the United States, may indicate
improper operation and maintenance of the sewer system,
and may also violate federal or state permits.
Sewer overflows are environmental enforcement priorities
for EPA. Since 1998, EPA has concluded 15 CSO enforcement
cases and 25 SSO enforcement cases, including more than
$14 million in civil penalties and $11 billion in injunctive
relief to protect public health and the environment. CSO
and SSO enforcement against seven major municipalities
alone has resulted in the elimination of approximately
14 billion gallons of sewage overflows per year, more
than $10.8 million in fines and more than $75 million
in environmental improvement projects. Since 2002, EPA
has settled sewer overflow cases with Los Angeles, Calif.,
Baltimore, Md., Baton Rouge, La., and Hamilton County/Cincinnati,
CSOs occur at combined sewer systems that were built
in the late 19th and early 20th centuries in U.S. cities
located mainly in the Northeast and the Great Lakes region.
These systems were designed to discharge directly into
rivers, streams or coastal waters when the combined volume
of sewage and storm water exceeds the capacity of the
system. Sanitary sewer systems do not combine storm water
with wastewater. SSOs have a number of causes: blockages,
pipe breaks, defects that allow storm water or groundwater
to enter the system, inadequate operation and maintenance,
equipment or power failures, and vandalism.
CSOs and SSOs contribute to beach closures, shellfish
bed closures, contamination of drinking water supplies,
and other environmental and public health concerns because
they discharge untreated wastewater that contains microbial
pathogens, suspended solids, toxics, nutrients, trash,
and pollutants that deplete dissolved oxygen. For the
first time with this report, EPA used currently available
data and health effects modeling methods to estimate the
number of gastrointestinal illnesses linked to sewer overflows.
For beaches that are regularly monitored, EPA estimates
that about 3,500 to 5,500 gastrointestinal illnesses per
year are caused by CSOs and SSOs. This data is available
for only coastal and Great Lakes beaches. EPA cannot calculate
a national estimate of the human health impacts of CSOs
and SSOs because sufficient water quality and health effects
data is not currently available for all recreational swimming
areas in the United States.
In 31 states and the District of Columbia, 772 combined
sewer systems annually discharge an estimated 850 billion
gallons of untreated wastewater and storm water, according
to the report. There are about 19,000 municipal sanitary
sewer collection systems in the United States. These systems
serve 160 million people in the United States, roughly
58 percent of the nation's population. EPA estimates that
between 23,000 and 75,000 SSOs occur annually, discharging
a volume of three to 10 billion gallons. Municipal treatment
facilities annually collect and discharge more than 11
trillion gallons of treated wastewater. According to EPA's
2000 Clean Water Needs Survey, over the next 20 years,
approximately $50.6 billion will be needed to reduce CSO
volume by 85 percent, and $88.8 billion will be required
to control SSOs.
In addition to fulfilling a 2000 congressional request
for information on CSO and SSO health and environmental
impacts, resources spent, and overflow control technology,
the report provides extensive new information to guide
EPA, state and municipal efforts to further reduce sewer
overflows. More information and a copy of the report.