If you live where the temperature drops below 32 degrees Fahrenheit then it is important to winterize all of your boat systems. This includes the fresh water tank, hot water heater, marine head, hoses, water pumps, water filters, air conditioner, generator and related sea strainers. The best way to accomplish this is by adding antifreeze to the fresh water tank, and open all faucets. Use non-toxic antifreeze designed specifically for freshwater, found at most marine and RV retailers. Environmentally friendly automotive antifreeze can be used on the air conditioning and generator seawater cooling hoses, pumps and strainers.