Orange County

Algae imparts ‘funny’ taste to Orange County water, but it’s safe to drink, officials insist

Cane Creek Reservoir, shown in an OWASA photo, is one of two reservoirs used by OWASA to provide drinking water. The other is University Lake.
Cane Creek Reservoir, shown in an OWASA photo, is one of two reservoirs used by OWASA to provide drinking water. The other is University Lake. Orange Water and Sewer Authority photo

Orange County’s water tastes “funny,” but it’s completely safe to drink, OWASA official Kenneth Loflin says.

Orange County Water and Sewer Authority (OWASA) Water Supply and Treatment Manager, Kenneth Loflin, said that the unusual flavor in OWASA-originated in recent weeks is the result of large quantities of algae growing in the town’s reservoirs — University Lake and Cane Creek Reservoir.

The algae secretes a compound that forms what is known as geosmin, which is not toxic to humans. If a person were to ingest “large amounts” of the stuff, Loflin said, they’d be fine.

UNC Health Care spokesman Jammie Williams said no patients have been admitted at UNC Hospitals as a result of drinking OWASA water since the odd tang first began to hit palates around May 12.

The extra flavor recently sampled from sinks across Chapel Hill is ofttimes described as “earthy.” OWASA administrators prefer to call it “musty.”

They blame geosmin and likely a drizzling of additional items — “anoxic water” with a probable dash of methylisoborneol (MIB).

These compounds are present in Chapel Hill’s reservoirs because of the decomposition of algae and other organic matter brought into the bodies of water when rain falls.

Human olfactory organs are extremely sensitive to geosmin.

“If you poured a teaspoon of geosmin into the equivalent of 200 Olympic-sized swimming pools, you would still be able to smell it,” Loflin wrote in email explaining the situation to concerned residents. “The general threshold for human detection is about 15 ng/l (15 nanograms per liter = 15 parts per trillion). However people with sensitive pallets can detect these compounds in drinking water when the concentration is as low as 5 ng/l.”

Heating water increases the volatility of the compounds and the smell is more easily detected when a person is taking a hot shower or drinking hot beverages containing geosmin.

OWASA was first alerted to the algae outbreak when residents began calling to complain about the strange taste on May 12 and testing was conducted confirming the presence of high algae levels.

“We profile our lakes each week ... There was a growth that was earlier than normal,” Loflin said. “We get a lot of questions about why it was worse this year and I don’t really have an answer for that. It could be that we had a large amount of rainfall about a week or so before this happened.”

About a week before the outbreak, some 6 to 8 inches of rain fell in the area and was followed by a hot and dry spell with daily highs climbing into the 90s. Algae needs a degree of moisture, nutrients and sunlight to grow. It appears recent weather may have formed the perfect environment for the algae to bloom.

Andrea Jost Ashdown is a resident of the Lake Forest neighborhood in Chapel Hill who is not at all happy about the state of the water flowing from her tap.

“Maybe it is safe,” Ashdown said, but she added that one of her neighbors tested their water — with what she understood to be a commercially available home water quality testing kit — which produced a “level red” result. A red-level finding, Ashdown claimed, is a poor result, leaving her to believe the water could be undrinkable.

Individuals have varying degrees of sensitivity to geosmin.

Jenn Kessing, a manager at Spanky’s Restaurant & Bar on Franklin Street in Chapel Hill, said only a handful of customers mentioned detecting anything funky about the taste of the water served at the restaurant.

“A handful of people over the last couple of weeks said something about it. And they drank the water anyway,” Kessing said. “It’s not really a smell. It’s like a slightly earthy taste.

“It’s not harmful. I’ve been drinking the water every day and its hasn’t done anything to me,” she added.

Loflin said OWASA started increasing the amount of powdered activated carbon in its water treatment processes as soon as the problem was noticed on May 12 to help resolve the taste issue.

An OWASA statement released Thursday said OWASA began “adding a chemical (sodium permanganate) to help neutralize taste and odor in water” pumped from the Cane Creek Reservoir on May 25 and is now primarily supplying town with that most successfully treated water.

“The truth is, here in Chapel Hill water is very expensive,” Ashdown said. “They need to figure out some longer term solutions for this. It is undrinkable and nobody around here is drinking the water anymore.”

Loflin said OWASA can’t provide a timeframe for its water to return to normal.

Colin Warren-Hicks: 919-419-6636, @CWarrenHicks