The Largest Sewage Spills in Recent History

A sign warning people to stay away from sewage contaminated water.
A sign warning people to stay away from sewage contaminated water.

Sewage spills are the overflow, spillage, or leakage of sewage from a sewer line, wastewater receptacle, or container or a wastewater treatment plant. Sewage spills can be onto or into a building, recreational waterway, land area or water body. A sewer spill can occur as a result of blocked or broken sewer mains or mechanical faults such as electrical power loss in pump stations or wastewater treatment plants. When either of the above happens, the sewage may enter the water directly from the point of overflow, rupture or through storm water drainage systems. Sewage spills in water bodies make the water unsafe for drinking, swimming and even carrying out other recreational activities such as jet-skiing, diving, and water-skiing. Secondary activities such as wading, fishing, and boating may also be affected to some extent.

The Largest Sewage Spills in Recent History

1. Tijuana Mexico

The massive sewage in Tijuana, Mexico has been the largest and the most recent sewage spill in history. About 143 million gallons of sewage spilled into the Tijuana in Mexico and flowed into the Pacific Ocean on the US side of the border. The spillage started on February 4th and continued until February 23rd, 2017. It was caused by repairs to a major sewer pipe. The incident has been dubbed the tsunami of sewage spills.

2. South Florida

In September 2016 about 29 million gallons of partially treated and raw sewage were unleashed into the waters of Tampa and Boca Ciega Bay and watersheds all around Hillsborough, Hernando, Pinellas, and Pasco counties in South Florida. Following a storm that briefly knocked out the city's power outage, the waste water facility experienced technical difficulties, and additional rains only made the spillage worse.

3. Waikiki, Hawaii

On March 24th, 2006, a 42-inch pressurized sewer line in Waikiki cracked sending more than 48 million gallons of untreated sewage flowing into the ocean. As a result, city officials in Honolulu, Hawaii, United States, were forced to post signs warning tourists on Waikiki Beach to stay out of the water. Engineers believe that the torrential rains that had poured since mid-February overwhelmed the sewer line, which was built in 1965. Since the city officials had no alternative, they pumped the raw sewage into the Ala Wai Canal, which emptied the sewer just west of Waikiki to prevent the spillage from backing up into hotels and people's homesteads.

4. Edinburgh, Scotland

In April 2007, the second largest sewage spill in recent history took place in Edinburgh when a pumping equipment at the Seafield Wastewater Treatment Plant in Leith failed, and the plant handles most of the capital's waste from an estimated 800,000 people. Approximately 100 million gallons of partially diluted and untreated sewage were pumped into the Firth of Forth at a rate of 1,000 liters per second. The public was warned not to take anything home from the beach and to maintain high standards of personal hygiene until the sewage was dispersed.

Effects Of Sewage Spills On The Environment

Sewage spills contain toxic substances which when disposed of in a body of water such as river, sea or ocean will dissolve or get suspended on the bed of the body of water. Such spillage usually causes water pollution, resulting in the deterioration of the quality of water which in turn affects the aquatic system and the biodiversity at large. The pollutants can seep into underground water deposits or enter rivers and other water bodies causing pollution. Such water is then pumped into households ultimately carrying pathogens and chemicals.

The Largest Sewage Spills in Recent History

Rank´╗┐LocationSewage (Gallons)
1Tijuana, Mexico143 million
2South Florida29 million
3Waikiki, Hawaii48 million
4Edinburgh, Scotland100 million

More in Environment