Venice > Sightseeing > Canals > Water quality, sanitation, maintenance

Venice's canals: Water quality, sanitation, and maintenance

Page 6 of 6
From: Canals of Venice

ABOVE: A pump sucks water from the dry side of a cofferdam in a Venice canal. (This area has been drained to allow repair work on the canal's stone wall.)

Water quality and sanitation

Venice's canals may be the world's prettiest sewers. Most residential buildings still dump human waste, laundry detergent, and other pollutants into the canals directly or via 16h Century tunnels called "gatoli."

For more on this, see "Sewage in Venice: How Does it Work?" by Luisella Romeo.

It's worth noting that in one scientific study over a three-year period, 78 percent of Venice's canals tested positive for Hepatitis A virus and enteroviruses.

As bad as this sounds (and it is bad), matters are helped slightly by two factors:

• The tides normally wash Venice's canals daily, pulling much of the sewage into the Adriatic Sea to decompose or get deposited on the beaches of neighboring towns.

• The water in Venice's canals and lagoon is a mixture of freshwater and seawater. Defenders of the status quo insist that the brackish water's salt content helps to keep bacterial levels under control.

BELOW: A dead pigeon and what appears to be bread (or perhaps something less salubrious) float in a Venice canal.

BELOW: This photo is from an old blog post titled "Dipping in the Doo-Doo." Our caption reads, "A visitor enjoys a fecal footbath."

BELOW: Not all of Venice's sewage goes directly into the canals. The city has an estimated 7,000 septic tanks (used mostly by hotels, government buildings, museums, and small businesses) that capture the output of employees and customers.

As you walk around the city, you may see pozzo nero ("black well") boats collecting sludge from those septic tanks.

BELOW: Typically, a pozzo nero boat moors at a building's water entrance or at a landing place near the septic tank that needs to be emptied. The boat's crew runs hoses or pipes from the boat to the septic tank. A pump on the boat then sucks up sludge for transportation to a waste-treatment plant.

Canal maintenance

Most of Venice's canals are fairly shallow: perhaps a meter or two in depth, or even less during exceptionally low tides (which, like acque alte or storm tides, have become increasingly common in recent years).

Without regular maintenance, sedimentation and sewage sludge can make the shallowest canals unnavigable for short periods.

Draining and cleaning out canals is the Venetian equivalent of repaving worn-out roads. As a bonus, drained canals give building owners a chance to repair stone foundations and replace rotted wooden pilings.

BELOW: In a drained section of a Venice canal, a cofferdam holds back water so workers clean out accumulated muck and trash. (For more on this, see our article on Maintaining Venice's Canals.)

BELOW: Most of Venice's buildings sit on top of wooden pilings like these. When the pilings are exposed to air, they decay and must be replaced by new pilings.

Back to: Canals of Venice (introduction)

About the author:

Durant Imboden has written about Venice, Italy since 1996. He covered Venice and European travel at About.com for 4-1/2 years before launching Europe for Visitors (including Venice for Visitors) with Cheryl Imboden in 2001.

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