Of course that's a risk. But it's always a risk when you're trying to "cheat" things into play. When you don't have that engine, things become much more difficult. That's why I would recommend a boatload of rainbow lands and mana rocks. If you've got 8 sources on the board that can tap for any color, then hard casting becomes possible too. You can still run all the Power Puff Girls and all their friends like Avacyn that have highly color intensive costs.
But don't take anything anyone is saying here to mean that you CAN'T build Jodah as a predominantly white deck. It just means we wouldn't do it that way. You do you. We are talking about the Commander format after all. Just about any combination is possible. If you really want the build to be predominately white, I would recommend adding in a second color as "primary". I would probably go blue. This would give you a lot of draw spells and perhaps counter spells. (And blue is one of the colors in Jodah's mana cost.)
Happy Brewing!