A half century after the passage of the landmark federal Clean Water Act, and almost four decades after the law’s deadline for all waters across the U.S. to be “fishable and swimmable,” 50% of assessed river and stream miles — 703,417 miles nationally — are so polluted they are classified as “impaired,” according to a new report by the Environmental Integrity Project.

The report, “The Clean Water Act at 50: Promises Half Kept at the Half-Century Mark,” uses state data to also show that 55% of lake acres that have been studied in recent years and 25% of assessed bays and estuaries are impaired — meaning they cannot be used safely for one or more public uses, such as swimming, fishing or as sources of drinking water. (A full spreadsheet of state data is available here).

“The Clean Water Act should be celebrated on its 50th birthday for making America’s waterways significantly cleaner,” says Eric Schaeffer, executive director of the Environmental Integrity Project and former director of civil enforcement at the Environmental Protection Agency. “However, we need more funding, stronger enforcement and better control of farm runoff to clean up waters that are still polluted after half a century. Let’s give EPA and states the tools they need to finish the job — we owe that much to our children and to future generations.”

The U.S. Congress passed the federal Clean Water Act in a series of votes from March to October of 1972 as a crowning achievement of the environmental movement. The law promised fishable and swimmable waters no later than 1983, and the elimination of all discharges of pollutants into navigable waters by 1985. But the Clean Water Act has fallen far short of achieving these ambitious goals. Among the reasons for that shortfall include the law’s weak to nonexistent controls for runoff pollution from farms, according to the new report. Other shortfalls include budget cuts to federal and state environmental agencies, the failure of government to enforce pollution limits, and toothless cleanup plans called Total Maximum Daily Loads (TMDLs).

One major problem, according to EIP’s report, is that EPA has neglected its duty under the federal Clean Water Act to periodically review and update technology-based limits for water pollution control systems used by industries. By 2022, two-thirds of EPA’s industry-specific water pollution limits have not been updated in more than three decades, despite the law’s mandate for reviews every five years to keep pace with advances in treatment technologies.

These outdated standards mean more pollution from oil refineries, chemical plants, slaughterhouses and other industries is pouring into waterways than we would have if these standards had been updated on schedule.

EIP’s report includes detailed maps and charts with the most recent available water pollution impairment data from all U.S. states. Among the state-specific findings of EIP’s study are the following:

• Indiana tops the list of states with the No. 1 most total miles of rivers and streams classified as impaired (or unusable) for swimming and water contact recreation (24,395 miles). (Ranked by percentage of miles assessed, Indiana ranks 11th. A full spreadsheet of all data for all states is available here.)
• Florida ranks first in the U.S. for total acres of lakes classified as impaired for swimming and aquatic life (873,340 acres), and second for total lake acres listed as impaired for any use (935,808 acres).
• California ranks first in the U.S. for most river and stream miles listed as impaired for drinking water (37,209 miles) and third for fish consumption (24,934 miles.)
• Louisiana ranks first for most estuaries classified as impaired for any use, with 5,574 square miles, or 92% of the waters assessed classified as impaired.
• Delaware has the highest percentage of its rivers and streams classified as impaired for any use, with 97% of the state’s 1,104 miles of assessed waterways listed as impaired for any use. Second most is New Jersey (95%) and third is Hawaii (91%).
• Iowa is representative of many states with farm runoff problems, having 93% of its assessed river and stream miles impaired for swimming and recreation (the fourth most in the U.S.) and 83% of its lake acres impaired.