The last time this happened to me I ended up replacing it. If it is a "State" brand water heater plan on doing the same. I won't deride them publicly but if I live to be 10,000 years old you would never hear me endorse them either.
Try opening up the tap at the bottom and see if it will drain. If no water comes out or there are chunks of rock-like material in the water then you can be pretty sure that the tank is full of sediment - time to replace it. There is no cost-effective way of fixing a tank problem.
Try opening up the tap at the bottom and see if it will drain. If no water comes out or there are chunks of rock-like material in the water then you can be pretty sure that the tank is full of sediment - time to replace it. There is no cost-effective way of fixing a tank problem.