From the League of Conservation Voters:

We all rely on having access to clean water -- for drinking, swimming, fishing and a variety of other purposes intrinsic to our way of life.
Unfortunately, there is now significant confusion over which waterways are protected from pollution under the Clean Water Act. This confusion has led to some water supplies being dropped from federal protection altogether -- allowing polluters to more easily do harm to vital waterways.
Thankfully, the EPA is stepping up. Recently, the agency drafted guidelines for determining whether a waterway, body of water or wetland is protected by the Clean Water Act – and they are accepting public comments until July 1st.1