1. Turn on your hot water and let it run.
2. Feel the temperature of the water. It should become warm within a minute of your turning on the hot-water faucet. If it is not, try another tap in the house to eliminate the question of whether it is a single tap that is not working.
3. If the water remains cold, turn the water off and check whether there is hot water being used in another portion of your home, because some hot-water heaters simply cannot provide hot water to more than a single place within a home. Check also to see if someone has recently used a large volume of water, which can also explain a lack of hot water.
4. Call an appliance repair specialist if you continue to fail to get hot water to come from any of your hot-water taps.