Rock-line steep ditches. Crown it annually. Relocate it if necessary. Work with your town road commissioner on preventing erosion of town roads. Sediment carries the nutrient phosphorus to lakes.
Turbidity threatens fish and other aquatic life.
Good driveway maintenance saves you money over the long-run. Don't add garbage disposals, washing machines or dishwashers unless you're sure your system meets current standards. Replace systems that don't meet standards. Pump septic tanks every 3-5 years. If any part of your septic system is closer than 50 feet to the lake, or less than 2 feet above the lake level, you could be polluting the lake.