United States
                      Environmental Protection
                                Office of Water (4503F)
                                Washington, DC 20460
June 2000
Water Quality Conditions in the  United States
A Profile from the 1998 National Water Quality Inventory
Report to Congress
States, tribes, territories, and interstate commissions report that, in 1998, about 40% of U.S. streams, lakes, and
estuaries that were assessed were not clean enough to support uses such as fishing and swimming. About 32% of U.S.
waters were assessed for this national inventory of water quality. Leading pollutants in impaired waters include siltation,
bacteria, nutrients, and metals. Runoff from agricultural lands and urban areas are the primary sources of these pollu-
tants. Although the United States has made significant progress in cleaning up polluted waters over the past 30 years,
much remains to be done to restore and protect the nation's waters.
Recent water quality data find that more than
291,000 miles of assessed rivers and streams do not
meet water quality standards. Across all types of water-
bodies, states, territories, tribes, and other jurisdictions
report that poor water quality affects aquatic life, fish
consumption, swimming, and drinking water. In their
1998 reports, states assessed 840,000 miles of rivers
and 17.4 million acres of lakes, including 150,000
more river miles and 600,000 more  lake acres than
in their previous reports in 1996.
Of the assessed ocean shoreline miles, 12% are
impaired, primarily because of bacteria, turbidity,
and excess nutrients. Primary sources of pollution
include urban runoff, storm sewers, and land disposal
of wastes. States assessed only 5% of the nation's
ocean shoreline miles.
                              States also found that 96% of assessed Great Lakes
                              shoreline miles are impaired, primarily due to pollut-
                              ants in fish tissue at levels that exceed standards to
                              protect human health. States assessed 90% of Great
                              Lakes shoreline miles.

                              Wetlands are being lost in the contiguous United
                              States at a rate of about 100,000 acres per year. Eleven
                              states and tribes listed sources of recent wetland loss;
                              conversion for agricultural uses, road construction, and
                              residential development are leading reasons for loss.
                              The states found that ground water quality is good
                              and can support many different uses. However,
                              measurable negative impacts have been detected
                              and are commonly traced back to sources such as
                              leaking underground storage tanks, septic systems,
                              and landfills.
                    Summary of Quality of Assessed Rivers, Lakes, and Estuaries
Waterbody Type
•*t •<*«*
=r 	 ^=

(sq. miles)
(% of Total)
(% of Assessed)
Good but
(% of Assessed)
(% of Assessed)
Includes waterbodies assessed as not attainable for one or more uses.
Note: percentages may not add up to 100% due to rounding.

     Leading Pollutants and Sources* Causing Impairment in Assessed Rivers, Lakes, and Estuaries

Rivers and Streams
Pathogens (Bacteria)
Urban Runoff/Storm Sewers
Lakes, Ponds, and Reservoirs
Urban Runoff/Storm Sewers
Pathogens (Bacteria)
Organic Enrichment/
Low Dissolved Oxygen
Municipal Point Sources
Urban Runoff /Storm Sewers
Atmospheric Deposition
*Excluding unknown, natural, and "other" sources.
Reporting Under the Clean Water Act
This National Water Quality Inventory is the twelfth
biennial report to Congress prepared under Section
305(b) of the Clean Water Act. It contains information
from each state on the quality of our nation's rivers,
lakes, wetlands, estuaries, coastal waters, and ground
water, along with information on public health and
aquatic life concerns.  It serves as a snapshot of water
quality conditions across the country.

To assess water quality, states and other jurisdictions
compare their  monitoring results to the water quality
standards they have set for their waters. These stand-
ards consist of  designated uses (such as drinking, swim-
ming, or fishing), criteria to protect those uses (such as
chemical-specific thresholds that should not be exceed-
ed), and an antidegradation policy intended to keep
waters that do meet standards from deteriorating from
their current condition.

Under Section  303(d) of the Clean Water Act, there is a
second reporting requirement—that states provide lists
of all of their impaired waters. These lists are then used
to prioritize state restoration activities. This is accom-
plished through the development of Total Maximum
Daily Loads (TMDLs),  calculations of the amount of a
pollutant that a waterbody can receive and still meet
water quality standards. A TMDL is the  sum of all avail-
able loads of a single pollutant from all contributing
point and nonpoint sources. It includes reductions
needed to meet water quality standards and allocates
these reductions among sources in the watershed.

Information reported by the states under the two
Clean Water Act reporting requirements is generally
consistent, although the 303(d) lists often include
specific information from more targeted monitoring
activities. This information clearly points to the need
to restore polluted waters and maintain the quality of
waters that currently meet standards. In August 1999,
EPA announced a new proposal for a strengthened
TMDL  program. Since August, EPA has worked to
incorporate comments from stakeholders and to
refine the proposal  to be an effective, common-sense
approach to water restoration led by states,  territories,
and tribes in partnership with federal and local gov-
ernments and local communities.
   For Further Information
   For a copy of the National Water Quality Inventory:
   1998 Report to Congress (EPA841-R-00-001), visit
   www.epa.gov/305b or call EPA's National Service
   Center for Environmental Publications at 1-800-