The horror drama's set, located at Cine Magic Riverfront Studios in Brooklyn, was flooded when the storm hit the East Coast, according to Entertainment Weekly.
"I went to check them out on the night of the storm at 10pm and they were under 6 feet of water - the entire complex," said studio owner Peter Kapsalis. "It wasn't in very good shape."
Some sets were apparently completely destroyed in the storm, though others may be able to be salvaged.
"The main sets stayed in place even with the water rushing in [but] everything is extensively damaged," Kapsalis explained.
A number of television shows that shoot in New York - including Elementary, 30 Rock and Person of Interest - halted production ahead of Sandy's arrival earlier this week.
ABC is expected to make a decision regarding the future of 666 Park Avenue in the coming days - the network is yet to commit to more filmed episodes, but has commissioned a further two scripts to be written.
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Watch a promo for 666 Park Avenue below: