Houseboats for Sale in Nassau County There are four houseboats for sale in Nassau County. Three are in Port Washington and the other is in Seaford. Asking prices range from $52,500 to $349,900. When buying a houseboat in Nassau County, some can be moved onto land and some cannot. You will need flood insurance and as of now the FEMA minimum for flood insurance is $1,500 per year. Currently, there is a 30 day waiting period for flood insurance policies according to the FEMA website. Living on a houseboat in Nassau County is like living in a HOA development. (0 comments)