Electric water heaters are dependable, but occasionally a mechanical problem can lead to a cold shower. Troubleshooting the problem is relatively straight forward and repairs are often possible. 

1. Blown Fuse

The first troubleshooting task is to locate the fuse in the breaker box that feeds the water heater, as a blown fuse means no hot water. Ideally your water heater is on its own breaker in the fuse box, but this isn't always the case. Once found, flip off the fuse completely then turn it back on. If the fuse keeps tripping, then your repair contractor will need to figure out the reason. It could be a faulty fuse or wiring. 

2. Thermostat Issues

Another point of failure on an electric water heater is the thermostat. Verify that it is set to the correct temperature, which is usually around 120 degrees Fahrenheit. This is hot enough to prevent bacterial growth in the water but cool enough to prevent burns. If the setting is correct, then the thermostat should be tested to see if it is time for a replacement. 

3. Element Failure

Most electric hot water heaters have two heating elements. The water heater may continue to supply hot water if one elements fails, but it will take longer for the tank to heat up after each use. Cold or lukewarm water occurs when both elements begin to fail. The good news is a failed heating elements doesn't require a full appliance replacement. Your contractor can simply replace the faulty elements. 

4. Hard Water Deposits

The minerals in your water, like lime and calcium, leave behind a residue inside a water heater tank. There are special devices, called anode rods, designed to capture the minerals so they don't damage anything. Over time, though, the rods become coated in buildup and no longer perform as well so buildup can coat the heating elements and reduce their ability to work. Flushing the tank and replacing the anode rods is needed. 

5. Limit Switch Malfunction

Limit switches are safety mechanisms designed to shut down the water heater in the event of a malfunction that leads to over heating and pressure buildup. A malfunctioning switch may shut down the heater when there is no overheating danger, thus resulting in cold or lukewarm water. Replacing the faulty switch, after verifying that it did activate due to malfunction and not a safety concern, fixes the problem. 

Contact a water heater repair contractor if your appliance is no longer heating water as it should.