I love the idea of living in a floating home. In fact, buying one is something I'm seriously considering. Of course, there aren't that many places where they're available. Seattle's Lake Union was made famous by Sleepless in Seattle, and then Portland, OR has floating home communities, as well as San Francisco. I'm sure there are some on the east coast, too. But what I want to talk about today is what you should know before you buy.
For one thing, you can't finance a floating home the same way as you do one on land. Interest rates are higher, and you definitely need %20-%25 to put down if you go through a bank (sometimes sellers are willing to make deals and help you finance it another way). This is because a floating home is considered personal property rather than a house.
Also, homeowners insurance is higher than with traditional landlocked homes.
And, much like condos, you're going to be stuck with homeowners dues. You'll also have to pay a slip fee, unless you are able to buy your floating home in a place that sells the slips too.
This doesn't mean you should get discouraged. It's just important to know what you're getting yourself into. For more information, visit this floating home FAQ.