I am a former resident of Marlton Lakes. I lived there for 10 years. If you love the outdoors it is a great neighborhood . Besides, the lake, you have hiking trails starting at the end of Fern Dr. You can explore for hours.
As far as the lake, there have been closings in the past. It was from fecal matter. People who live on the lake import ducks. When the weather gets really hot, and the lake evaporates a little the fecal count goes up. Not from septic, but ducks and native geese.
We never had issues with water. I know state testing was done after we moved. The septic was fine while we there. Our house never flooded but we were not on the lake, we were across the street from it. As far as I know, our neighbors on the lake did not have flooding issues.
I would be concerned about electrical wiring. Some houses still have aluminum wiring and not copper.
If you have any more questions I can help you with let me know. I am an agent at Keller Williams Realty in Medford. My cell I s609-410-8111.