I had to replace my electric hot water heater a few days ago because the dip tube was disintegrating. It was 14 years old, so I felt it was time for a replacement. The plumber came out and replaced it with a comparable 50-gal electric water heater. Later that evening, I discovered that we were not getting enough hot water. I called the plumber back out. He determined that the power input into the hot water heater was only 120V, not 240V. The original HWH was 240V, and it met our needs. My questions are:
1. Are there any 50-gallon hot water heaters that are 120v?
2. Can a 240v hot water heater run on 120v?

I am selling this house soon, so I don't really care about long-term efficiency. I want to minimize my current expenditure, but I don't want to end up with something that will fail a house inspection.
Any advice will be greatly appreciated.