Is your water heater running up to speed?
One of the more obvious issues that can arise is if you see that there is a leak in the tank. All you need to do to diagnose this problem is check and see if there is water near or around the base of the tank. Another place to check for leaks is around the pressure relief valve, this is a sure sign that something is amiss with the tank. Some of these leaks can be easily fixed by qualified professionals, but when you see water on the floor by the tank it's time to have professionals come in and help you.
Finally, if you continue to see rust in your water the water heater might be the culprit. If too much rust and sediment build up your tank will start to have problems. This is common among water heaters that are older. If you start noticing that there is a lot of rust in your water then you'll want to call professionals to come and check out your water heater before it's too late. The last thing you want is to have the tank fail and cause water damage. If you see any signs of trouble have a professional come and check it out.