Over 10 billion gallons of raw and partly treated sewage gushed into waterways and bubbled up onto streets and into homes as a result of Hurricane Sandy — enough to cover Central Park in a 41-foot-high pile of sludge, a nonprofit research group said in a report released on Tuesday.

The group, Climate Central, said about 94 percent of the sewage flowed into rivers, canals and bays in New York and New Jersey, the states hit hardest by the storm that came ashore six months ago. In New York City alone, 1.6 billion gallons spilled into area waterways.

Alyson Kenward, the principal author of the report, said in a teleconference that rising seas and strengthening storms, a result of climate change, could increase the threat of similar spills in the future. She urged an overhaul of the region’s wastewater infrastructure.

“Our sewage infrastructure isn’t designed to handle this type of storm surge,” Dr. Kenward said.

Hurricane Sandy exposed serious shortcomings in the region’s infrastructure. Dunes were breached, and subway lines and tunnels were flooded. After the storm, gasoline was often difficult to find, and electricity in some places was out for weeks.