It turns out there were high bacteria levels due, in part, to goose droppings and the torrential rain we've had recently.
"We have a full water shed up above the lake in which storm water runs off roads, parking lots, farm fields, the forest itself and everything contributes to the bacteria levels," said Johannus Franken, the Atsion Area Supervisor.
Atsion's dark cedar water, typical in the Pinelands, is tested weekly. Bathers we talked to didn't seem the least bit worried about the week-long lake closure.
"I've been in the Cooper River. I don't think anything gets worse than the Cooper River, so..." said Lauren Webber of Haddon Township.
"I have no problem swimming in this. This is good. The state tests it. They say it's okay, that's good enough for me," said Dan O'Neill of Northeast Philadelphia.
Atsion Lake is a popular spot. At $5 a carload during the week, they offer kayaking, hiking, picnicking and a lot more. It's an affordable alternative for folks who don't want to go to the shore.
"You don't have to spend money. It's only $5 or $10 to get in and you have fun all day long. We bring our food, we bring our girls, it's lovely," said Ella Mobley of Gloucester City.
"I like the open spaces. It's not overly crowded, I like all the trees," said Anne O'Neill of Northeast Philadelphia.
The lake is the main draw, of course, and park officials are hoping the rain will stop and the geese will go elsewhere so bathers can swim without worrying about what's in the water.