It’s very simple. Turn off your water running to your outside pipes and drain the faucets to make sure there isn’t any water left in them. 

It could be that your water heater is coming to the end of it’s life. Make sure you flush out your water heater frequently. By flushing out your water heater at least once a year it can help extend the life of a water heater. Water heaters should typically last 10 years.