Phosphorus levels are higher downstream of Atlanta than upstream.

This chart shows the amount of phosphorus, in tons per year, upstream and downstream of the Chattahoochee River at Atlanta, which is a major source of the local water supply. The amounts of phosphorus downstream of the city have decreased about 77% from the highest levels in 1984 because of both voluntary and mandatory restrictions on phosphorus detergents in the city. As the bottom line shows, though, the total phosphorus load in the more agricultural area north of town continues to increase.