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What are the bacteria levels in Charlotte-area lakes? See what the water quality is

Evan Moore
·3 min read

Charlotte-Mecklenburg Storm Water Services issued a no-swimming advisory for a Lake Norman cove after an estimated 460 gallons of sewage spilled into it.

The spill, which happened on Torrence Chapel Estates Circle in Cornelius, was stopped on Thursday, and the advisory was lifted the same day, The Charlotte Observer reported.

In the event of a sewage or chemical spillthat is considered a public health threat, Charlotte-Mecklenburg Storm Water Services issues a advisory to alert the public of unsafe water conditions, according to the department.

Swimming while an advisory is in effect can lead to illnesses, such as diarrhea, skin infections and respiratory infections, according to the N.C. Division of Environmental Health.

Here’s what you should know about bacteria levels in Charlotte area lakes.

How are bacteria levels measured in Charlotte-area lakes?

Lake Use-Support Index (LUSI) scores – which measure surface water quality – are updated every other month and represent data collected from monitoring sites, according to Charlotte-Mecklenburg Storm Water Services.

Scores range from 0-100, with 100 indicating the best water quality, and are based on four categories that show the most important indicators of environmental health, including:

  • Bacteria: fecal coliform and e. coli

  • Metals: arsenic, barium, cadmium, lead and zinc

  • Nutrients: chlorophyll A, nitrogen and phosphorus

  • Physical: temperature, pH and dissolved oxygen

Here are the average LUSI scores for each lake in the Charlotte area from March:

How often are lake waters checked?

According to Charlotte-Mecklenburg Storm Water Services, water quality in lakes is routinely monitored throughout Mecklenburg County, but it is impossible to know, at any given time, whether or not the water is safe for swimming.

The water is generally safe to swim in, but cove closures -- which happen when the amount of bacteria in the water gets too high -- occur on occasion, Charlotte Water Public Affairs Manager Jennifer Frost told the Observer last year.

“Both Mountain Island Lake and Lake Norman are quite large,” Frost said. “They have a good amount of flow, and there’s really good turnover, so the water is good. It takes quite a bit for there to be any kind of negative impact on water quality.”

Frost explained that both lakes are regulated as recreational water, meaning any company that discharges into the water has to maintain certain standards so they are safe for public use. The lake is also monitored around the clock for changes in temperature, pH and conductivity, Frost said.

Natural bodies of water can contain organisms, including bacteria, amoebae, and parasites, that can cause illnesses in humans, according to NCDEH. Some of those illnesses include diarrhea, skin infections, respiratory infections and even wound infections that can be life-threatening.

How to monitor lake water

Swimmers should always monitor the Charlotte-Mecklenburg Storm Water Services’ Facebook and Twitter pages for swimming advisories, the agency says.

Here are some other tips from NCDEH on how to stay safe in the water:

  • Avoid getting the water in your mouth.

  • Hold your nose shut or use nose clips so water doesn’t enter your nose.

  • Don’t dig in the sediment in shallow areas.

  • Don’t swim in lakes if you have open wounds or sores.

  • Shower after swimming in the water.

  • Treat any wounds you get while in or near the water.

  • Seek medical attention if you become ill or develop symptoms of an infection.