How to convert natural gas water heater to propane?

In the old days it was fairly easy but with product liability issues, you may have a hard time getting owner installed parts. You will need to contact the manufacturer to see if it is possible and where to get a conversion kit. You will need orifices and a gas valve as gas pressures are very different. Sometimes it is cheaper to get a new propane unit and sell the old heater as aftermarket prices are typically high.