After years of neglect, New Jersey is addressing problems associated with aging sewer infrastructure, some of which is more than 100 years old

During big storms, the aging infrastructure set up to treat wastewater often breaks down, spilling diluted raw sewage into the state’s rivers and the New York/New Jersey harbor estuary. The problem is caused by combined sewer and stormwater lines, which cannot cope with the runoff from heavy rains. The result is more than 7 billion gallons of untreated sewage dumped into waterways each year from 217 outfalls (New Jersey Future, “Ripple Effects”).

After years of neglect, the state and 21 cities are beginning to address the problem, requiring local governments and agencies to draw up long-term control plans to deal with the issue. By the beginning of next year, the state Department of Environmental Protection is expected to issue final permits, which give the cities three years to develop their plans.

The needed upgrades will not be cheap: They’re likely to exceed billions of dollars when all the work is done. Where the funds will come from remains to be seen, but in the end, households could see a spike in their sewer bills.

Even with the funding dilemma, officials say the cities need to take action. Beyond causing the closure of beaches and shellfish beds, the problems caused by the so-called combined sewer overflows (CSOs) sometimes lead to sewage backups in homes and streets.

Here is a list of the 10 sites with the largest number of CSOs, and a look at what happens when it rains heavily — or sometimes during regular storms.

1. Bayonne

The Hudson County community has the distinction of having the most outfalls — 30, all told. The result is an estimated 930 million gallons discharged each year from the lines, most of which are 80 to 100 years old. Sewage backs up in low areas when high tides combine with intense storms.

2. Camden City

Camden ranks just behind Bayonne in the number of outfalls — with 29. They dump 683 million gallons of diluted sewage into the Delaware River annually. The city’s system was built in the latter half of the 1800s; Sewage backs up into homes and streets during regular storms.

3. Elizabeth

The Union County city has 28 outfalls, although it is not known how much those lines discharge each year. Built of brick and clay, groundwater infiltrates the lines through cracks and leaks are a likely issue.

4. Paterson

It 24 outfalls discharge an estimated 702 million gallons into the Passaic River Like Elizabeth, many of its pipes, some dating back to the 1860s, are brick. When the river is high, sewage backs up during intense storms.

5. Jersey City

While the Hudson County city has invested in dealing with its CSO problems, it sill has 21 outfalls discharging into waterways. The amount discharged is not available. Parts of the system are in good shape; other components are falling apart. The city is under a U.S. Environmental Protection Agency consent decree to upgrade the system, thus preventing sewage backups during high tides.

6. Newark

Many of the city’s lines are more than 100 years old, and some are built of brick. The state’s largest city has 17 outfalls, but dumps more diluted raw sewage into waterways than any other community — an estimated 2 billion gallons each year. Stormwater runoff during major storms causes flooding in low areas.

7. Perth Amboy

The city has 16 outfalls, which discharge about 840 million gallons into waterways annually.

8. North Bergen Sewerage Authority

With a total of 10 outfalls, the authority ends up spilling 410 million gallons each year.

9. North Hudson Sewerage Authority

The authority, which includes Hoboken, Union City, Weehawken, and West New York, also has 10 outfalls. Each year, it discharges more than 1 million gallons into waterways.

10. Gloucester City

The community has sevenoutfalls with 74 million gallons of diluted sewage discharged into the Delaware River each year.