Be a responsible animal owner. Don't leave their waste on the ground.
This is an easy one: be a responsible animal owner and clean up after your pets. Not just when you are out and about with them, but also around your home and yard. Never throw animal waste into stormwater drains or catch basins on the side of the road—they drain directly to a local waterway, and sometimes to a beach.
If you have livestock on your property, follow best management practices to protect your local waterways. Keep livestock out of streams. Manage manure storage and applications to prevent polluted discharges from your land during rain.