Regular home water heaters are not suited or legal for mobile home use. For instance a regular water heater is not made to be installed on combustible flooring. In a mobile home there is a space issue so you will have problems with clearances to combustibles. I would spend the extra money and buy one made for mobile homes. (see the article) PlumberTom
Very different from site-built - Water Heaters
I'm very sorry, i assumed it was gas. I can't think of anything they can do to an electric water heater except maybe make it smaller to make it a Mobile home water heater. I would just be very carefull of the electrical requirements of the water heater and make sure you have enough power. They make all different sizes and single or double elements. If there is two elements they don't on on together, when cold the top element goes on and then it reaches temperature the bottom one goes on. Shorter water heaters that have less capacity Example a 30 gallon will sometimes have just one element.
If you are replacing an existing water heater, try to use one with a similar size element. they are rated in watts, and most residential water heaters are 4500 watts . I've seen that some heaters are 3500 watts however. PlumberTom