Heavy rains like the Austin area saw Tuesday morning often send large amounts of pollution into creeks and streams.
It appears the main culprits are fertilizers from yards, as well as gas and oil from vehicles.
"As people develop land it has a tendency to degrade water quality and that is why we are looking at how we can put in water controls to make the water quality better," said Roger Glick from the Watershed Protection Department.
There are currently about 30 water-monitoring sites around Austin that are checking the levels of pollutants in our storm water runoff.
"Any oils from the cars going by any of the fertilizer running off your yard are going to come out and be more evident after a storm," said Kathy Shay.
"We should definitely all care about the amount of pollution coming down our creeks and streams and that is because they feed our water supply that most of us drink from," Shay said.
There are several things people can do to lower the amount of pollution in the water.
Some examples include using organic fertilizers, washing cars with soaps that don't include phosphates, and keeping cars well-maintained so they don't leak fluids.