Do not use caustic liquid drain openers on a drain that is completely clogged. It can severely damage your pipes. Periodically drain several gallons of water from your water heater. This removes sediment from the bottom of the tank to increase heating efficiency and prolong tank life. Wrap outdoor or crawl space pipes with electric heat tape or insulation to prevent freezing.
Liquid fats solidify in the cold drains pipes and create clogs.
Check under sinks for moisture or small leaks. Leaks under sinks should be repaired quickly to avoid damage to cabinets and floors. Use a strainer in bathroom drains. This will prevent hair and soap pieces from clogging drains. Make sure overflow holes on tubs and vanity are clear and open to prevent water damage to floors and ceilings.