It all really depends on your towns water treatment plant and how good it is. The chemicals, including chlorine/chloramines, found in tap water won't harm your reptile(s) as much as they will with fish, but they won't be beneficial either. From what I can tell, it seems as though reptiles avoid water with higher levels of the chemicals, leaving them more likely to be dehydrated.
In my opinion, if you have any doubts about the quality of your tap water, you should use an alternative for your reptile, otherwise go ahead and use it.
I use water conditioner for the water I give my reptiles because I don't like the taste of the tap water myself, and treating the water isn't that much of a hassle in my opinion. I use reptisafe which I can can find for about $5, and it uses 2 drops per cup of water. You can also use the same water conditioner you would use for a fish tank, as long as it doesn't have any additives (like for their slime coating).
The other option I know people use, are brita water filters. They might not take the chemicals out entirely, but they take out enough that it's not a problem.
The only thing you should avoid using is distilled water. Because reptiles rely on some of the minerals found in water, and distilled water removes those minerals, it can do just as much harm, if not more, as giving them water with the chemicals in.