Check sinks, tubs, and showers for proper drainage. Remove hair from drains. Check the pressure relief valve on the water heater. Open it to see that it is working. Check for signs of leaking or rusting.
Some manufacturers recommend that a small amount of water be drained periodically from the tank.
Replace old batteries. Keep a fire extinguisher handy for use in kitchen and near any wood-burning stove or fireplace. Check the extinguisher gauge for proper pressure. Keep outside security lighting in good repair. Lighting exterior grounds helps discourage prowlers.