will a heating element from a water heater will bring about 2 gallons to 100 deg Celcius to use with a home made steam distillation setup?  will it work?

That is impossible to say without more information about the setup.

It probably would,if your water heater was powerful enough.

It'll take about 30 minutes to bring 2 gallons of water from 20C -> 80C using a 1500W (ie 1500J/s) heater assuming adiabatic conditions. That's fast enough to get it a boil as long as nothing is drawing away heat too quickly. I wrote about the calculations, but I don't see them here.

It takes about 4J to heat 1g of water 1C. You need to heat about 7.5L by 80C. You can do the math and see that I'm not too far off with my estimate.

Your setup will be fine.

great thanks guys and thanks for the math chromic....  actually, what i have is one of those ice tea dispensers as the retort.  and im gonna have to somehow rig up the heating element in there.