Forty years ago today, Congress passed the Clean Water Act in response to citizens' demands to stop the pollution of our rivers, lakes and streams. But like many big birthdays, the Clean Water Act's 40th is both a moment for celebration and a reminder of work yet to be done.

In the last four decades, we have made progress towards clean water. Our rivers are no longer catching on fire, and we can now swim and fish in many more of our waterways.

But we still have a long way to go. The majority of Americans live within 10 miles of a polluted river, lake, stream or coastal waters. Pollution from industrial agribusiness plagues waters from the Mississippi River to the Chesapeake Bay, where massive dead zones encompass up to a third of its waters every summer. Moreover, we still have billions of gallons of sewage overflows and thousands of beach closings and advisories each year. In addition, industrial sources still discharge more than 200 million pounds of toxic substances directly into our waters each year.

And in the 21st century, our waters face a grave new threat: across the nation, a frack-fueled drilling boom is putting our water at risk in several ways. Fracking produces billions of gallons of contaminated wastewater laced with toxics like benzene, heavy metals, and even radioactive material. This wastewater has contaminated drinking water sources from Pennsylvania to New Mexico. In addition, frack fluid chemicals are leaking and spilling into streams and creeks, and methane and other substances are contaminating nearby residents' drinking water wells. Finally, with nearly a million gallons of water used in each frack job, this dirty drilling is placing an added strain on water resources.

Clearly, we need stronger rules and policies to safeguard our water. Yet two obstacles bar the path to tougher protections. First, our nation's clean water laws are now hampered by significant loopholes and exemptions. The very reach of the Clean Water Act has been undermined by a set of court decisions. As a result, nearly 60 percent of our streams -- including those feeding drinking water sources for 117 million Americans -- may no longer be protected. This loophole has hobbled literally hundreds of enforcement cases against known polluters. Similarly, despite its wide-ranging damage, fracking is exempt from key provisions of several laws designed to protect our water and our health -- including the Resource Conservation and Recovery Act (RCRA), the Safe Drinking Water Act, and the Clean Air Act.

Second, big polluters--from oil and gas to mega-agribusiness -- are working to further undermine the laws and regulations that protect our waterways. For example, in the 112th Congress, the House of Representatives voted no fewer than 38 times to dismantle the Clean Water Act, including passing a package of clean water act attacks as the last vote before they adjourned for elections.

Thus, at the 40-year mark, clean water stands at a crossroads. To truly protect our rivers, streams, and drinking water, we will need to overcome these two obstacles -- to reverse the loopholes in our laws and to confront and turn back the heavy guns of polluting interests in Washington. And as with the passage of the Clean Water Act itself, it will take nothing less than the sustained effort of citizens raising their voices to do so.

In April 2011, the U.S. Environmental Protection Agency (EPA) announced a draft guidance aimed at restoring the Clean Water Act's protections to all of our nation's waters. But while industry has sought to derail this effort, Environment America and our allies have demonstrated that citizens still want stronger protections for our waters, not weaker ones. More than 300,000 individuals -- plus hundreds of elected officials, farmers, and small businesses -- have all voiced support for EPA's move.

But even after we restore the jurisdiction of the Clean Water Act -- and I believe we will -- there is much more we must do to protect our rivers, lakes, and streams. We need new rules to rein in pollution from factory farms, new standards to curb runoff pollution and sewage overflows, and the political will to enforce the protections we have. And for every one of these steps, it will take a concerted effort of citizens to make it happen.

So on its 40th birthday, here is the best present we can give to the Clean Water Act: our commitment that we will always be here to fight for clean water -- for the next 40 years and beyond.

Follow Margie Alt on Twitter: www.twitter.com/EnvAm