The group said the estimated cost of repairing damage to sewage treatment plants after Sandy is nearly $2 billion in New York and $2.7 billion in New Jersey.
Alyson Kenward, the lead author of the report, said that treatment facilities should raise power generators and other critical components to minimize future overflows. She also said separating sewage lines from storm water overflow pipes can also help, though that's an expensive undertaking.
"These facilities do by design have to be relatively close to the water," she said. "They are always going to be vulnerable to coastal flooding."
Kenward said quick work of treatment plants saved billions more gallons of untreated sewage from entering waterways.