Having no hot water can be irritating, especially in the winter months. An absence of hot water generally occurs as a result of all the hot water in the tank being used up--for example, by running both the washing machine and dishwasher at the same time. However, if that is not the cause of the problem, it's not difficult to troubleshoot your water heater to locate the issue.
Check the circuit breakers in your fuse box. If the fuse has burnt out or the circuit breaker has tripped that directly controls the electricity for your heater, it will not work. Reset the breaker or replace the fuse as necessary and restart your water heater.
Look at the thermostat setting. If it is set too low, that may be the problem, especially in colder months when the temperature of the incoming water is already very low. Increase the thermostat setting to a higher temperature.
Open the burner access covers and check the status of the pilot light. If you have a gas-powered water heater and the pilot light goes out, the water will not be heated. Open the covers with a screwdriver and look for a single small flame. If it is out, re-light it.
Check the pipes from the water heater. If the pipes that are carrying the hot water to the rest of your home are leaking, you will not get a sufficient amount of hot water coming out of your faucets. Look for pools of water on the floor or listen for a dripping sound to identify the location of the leak.
Look at the color of the water coming out of your faucets. If it is discolored, it is possible that there is a build up of sediment in the water heater that is preventing the water from getting hot. Drain the tank completely and flush it out with clean water to alleviate the problem.