People drinking tap water across the Miami area this week may notice the smell and taste of chlorine as Miami-Dade launches the annual cleaning of its underground pipes.
The “cleansing” began Monday and runs through Nov. 19. The county issued an advisory about the likelihood of changes in odor and taste in Miami-Dade’s drinking water.
Like most water systems across the country, Miami-Dade regularly uses chlorine to disinfect the drinking water it sends to roughly 2.3 million people each day. Miami-Dade uses “chloramine,” typically a mix of chlorine and ammonia, on a regular basis. But for cleansing every year, it switches to a different type of chlorine known as “base chlorine,” which tends to have a more detectable taste and odor.
“People call every year after the first couple of days” of testing, said Adriana Lamar, spokeswoman for Miami-Dade’s Water and Sewer Department. She said the chlorine test spreads as the treated water moves farther out into county pipes. “It depends on how far you are from the plant,” she said. “By the end of the [first] week, I start to smell it.”
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Miami-Dade uses its main plants in Hialeah and the Kendall area, as well as smaller ones in South Dade, to distribute the cleansing compounds in pipes throughout the county. Only a few cities — Homestead, North Miami and North Miami Beach — have their own water plants.
The Centers for Disease Control and Prevention says the shift from chloramine to base chlorine is common, and allows water systems to clean out a “scum” layer that can form in pipes that makes “killing germs more difficult.”
Erik Olson, director of health programs at the Natural Resources Defense Council, said the shift to regular chlorine is a fairly common tactic in water systems across the country and should not raise concerns. While the substance itself does not raise health concerns, prolonged exposure to organic matter in a water system, such as leaves and dirt, can create byproducts linked to cancer, he said.
As a result, water systems typically make a brief shift to base chlorine and then flush out the system, often using fire hydrants.
“The bottom line is it’s not a problem, as long as it’s short-term,” he said.