Recently I changed the elements in my water heater. Now I have about half the quantity of hot water than before. What do I do to check the problem?

Any chance you turned on the heater BEFORE it was full of water? It happens all the time and it's the best way to burn out a new element. Why did you change the elements in the first place?

I was receiving high utility bills and the electrical provider advised me to change the elements in my water heater. It had been several years since I had done that, so I took their advice. After installing the elements. I bled the air from the lines while filling the tank and was sure the tank was full before energizing the elements.

But everything worked OK BEFORE you changed them?

Yes. I bought new thermostats today and will install them shortly, and if that doesn't work I assume when I purchased new elements, one was bad from the manufacturer. Would you agree with that?

More than likely the elements are the wrong wattage. How old is the water heater? And quit listening to the electric company for advice.

They are the right wattage. 4500 watts. And I agree with your advice about listening to the utility company

Any chance you mis-wired the thermostats? They work sequencially, never together.

The wires were taken from the elements only. Not the thermostats, so there would be no way they could be wired wrong. 2 wires per element (top and bottom). I haven't replaced the thermostats yet.

If you have a voltmeter, check what's coming to the thermostats.. reset the breaker also. Seems unlikely you have a bad element, but you can test them without removing them if you have an ohm meter.

I don't have a vltmeter, but do have a voltage tester. It shows 240 volts comining to the top of the top thermostat, but I can't get a reading of 240 to either of the elements. I can only get a reading of 120V. To each element.