Honestly, I limit the amount of time that my kids swim in the Chesapeake Bay - I live on the Bay in the Annapolis area and have a community beach but we rarely use it because the Bay is not clean and has a lot of bacteria in it. When my kids do swim in the bay, they actually come out with a film of dirt on them - it is really gross and especially noticeable around their mouths for some reason. There is a website that publishes the water quality for all bay front areas in my county, so I check it before allowing my kids to go in. It certainly isn't a place I would plan a beach vacation around. I would still consider the Atlantic beaches - you can rent condos on the bayside (not the Chesapeake Bay, it's called the Assawoman Bay in MD and in Delaware, there are two Rehobeth Bay and Indian River Bay). There is plenty more to do with kids at the Atlantic beaches than renting a condo on the Chesapeake Bay, which I think you would be hard pressed to find as most areas are residential and not commercial/vacation rental areas.