During Memorial Day weekend, residents along the Gasper River discovered numerous dead fish washing up onto banks and floating down the river.

The subsequent state investigation revealed low dissolved oxygen levels and the presence of nutrients and E. coli in an estimated 5-mile stretch originating near the Clear Fork Creek and Gasper River crossing.

While Kentucky Energy and Environment Cabinet officials continue to search for the source, the contamination has caused fear among river-adjacent residents who rely on well water.

HydroAnalytical Lab, the state-certified water quality laboratory, has been receiving calls from residents wondering whether they should test their water, according to Dr. Jason Polk, a Western Kentucky University professor and director of the HydroAnalytical Lab, which is part of the WKU Applied Research and Technology Program.

“Anytime we see some issue with water, we get calls from people curious about what’s in their water and what they can do about it,” Polk said.

Since the investigation is in the early stages, Polk suggested people should consider waiting until they’re informed about a potential issue before requesting a potentially unnecessary test or testing for the wrong water quality parameters.

“It’s not uncommon to find bacteria or nutrients in all of our waters around here. It depends on if they’re higher than normal,” Polk said.

People drinking well water should have the water tested at least once per year. Depending on where the residents live and their relation to potential threats like chemical plants or farms, they might need to test their water every three to six months, Polk said.

If residents notice an odor or an unusual taste, or think their water has been exposed to a spill or runoff, it’s probably a good idea to get the water tested. But the first step should be contacting the local health department or a utility, Polk said.

Testing isn’t inexpensive – it could cost residents $200 or more – so it’s important to first determine which tests are needed. Labs can test more than 100 parameters for water quality, but residents could request a baseline package to test for E. coli, nutrients like nitrates and phosphates, pH and lead.

A potential issue with testing is that there has to be multiple “systematic” tests to get an accurate read of water quality in karst areas, as factors like rain events and flooding could impact results.

“If they feel like there’s a valid concern or they feel like something has changed, they can get their water tested … it’s not difficult to do,” Polk said.

The labs accept water samples and run the tests. Further analysis and investigation requires an additional step, such as contacting the health department.

For residents wanting to err on the side of caution, they can employ safety measures such as boiling water before drinking it or buying bottled water. The Centers for Disease Control and Prevention recommends bringing water to a boil for at least one minute, then letting it cool and storing it in a sealed container.

The Kentucky Division of Water regulates public water systems, which provide about 95 percent of state residents with drinking water. Public water runs through a process of chlorination, filtering and disinfection to eliminate bacteria and contaminants.

Neither the division nor the Environmental Protection Agency monitors private wells, so the state recommends homeowners using private wells for drinking water have the water tested annually.

In regards to the current situation, “anyone who is concerned should have their water tested,” said John Mura, communications director for the Kentucky Energy and Environment Cabinet.

In addition to the HydroAnalytical Lab, IEH in Scottsville and Glasgow Water Company Micro Lab offer state-certified water quality testing services.

Thus far, water samples have not indicated a need for state water advisories, according to Mura.

“If the state felt that there was a continual health problem, we would be addressing it,” he said.

David Landreth, who lives near the Gasper River, swam in the river after the fish kill event and said he noticed skin bumps on his face and body afterward. He has since observed dead frogs, turtles, crayfish and a snake, in addition to the countless dead fish, he said.

“Why did creatures that come up for air die?” Landreth said. “There has not been a caution or warning issued publicly about the river having some contaminant that killed not only fish, but everything in the river.”

For Landreth, the Gasper River has been essential to his life. He “lives off the grid” and routinely swims and fishes in the river.

“I drink the water out of this river,” Landreth said. Now, “I’ll stomp through it, but that’s about it.”

“I don’t want money out of this, but by god I want my river to get back to normal.”

In the summertime, most fish kills occur from the low concentrations of dissolved oxygen in the water. Though the cause can be natural, decreased dissolved oxygen concentrations often indicate the presence of bacteria or nutrients, commonly from untreated sewage, fertilizer runoff or manure, according to the U.S. Geological Survey.

E. coli is most commonly found in cattle farms where the bacteria can live in the intestines of healthy cattle. E. coli, which can originate from infected human or animal bowel movements, can enter the water system through sewage overflows, sewage systems malfunctions, polluted stormwater runoff and agricultural runoff, according to the CDC.

At this time, it’s unclear what caused the Gasper River fish kill. Biologists involved in the investigation have suggested that it could take years before aquatic life returns to levels preceding the fish kill event.

“We hope to have some answers to explain this in the near future,” Mura said.