11 Billion Gallons of
Sandy Sewage Overflow

Explore where sewage overflows happened during Hurricane Sandy,
what caused them, and how treated each overflow was.

  • All Overflows
  • Types of Overflow
  • Causes
  • State Totals
Sewage Overflow During Sandy

Sandy caused more than 10.9 billion gallons of sewage overflows. Roll over each circle below to see the different size and location of each documented overflow.

How much?

Legend: Circles are color-coded by state sized according
to the volume of overflow in gallons.

  • CT
  • DC
  • DE
  • MD
  • NJ
  • NY
  • PA
  • RI
  • VA
1 billion gallons
100 million gallons
10 million gallons
Olympic-size swimming pool
660,000 gallons
Partially Treated

7.45 billion

About 70 percent of the overflows contained partially treated sewage, which in most cases did not meet the national treatment wastewater standards. Most of these overflows were at least disinfected before being released into waterways, but in rare cases may only have been filtered.

Untreated Sewage

3.45 billion

About 30 percent of the overflows were entirely untreated before entering rivers, streams, or the ocean

Sandy's record storm surge inundated many coastal treatment plants and overloaded pipes and pumping stations. The storm surge flooded treatment tanks, knocked out power, caused mandatory evacuations in select neighborhoods, and forced plant operators to send partially treated and untreated sewage into nearby waterways.

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