Nearly two dozen utility districts across the state violated a drinking water standard in 2017, according to the Tennessee Department of Environment and Conservation.
Those violations stemmed from elevated levels of a contaminant in drinking water known as haloacetic acids.
When consumed above the legal limit over many years, haloacetic acids may increase the risk of cancer, according to the Environmental Protection Agency.
Regina Jackson said she received a series of notices from her local utility district that made her think twice about her tap water.
"It's very concerning to me," said Jackson, who lives in the Frankewing area of Giles County. "I'm just helpless with the whole situation, that's why I called [the I-Team]."
Jackson received four letters, most recently in late November, stating her water contained a contaminant that when consumed over the legal limit in excess over many years, "may increase a risk of getting cancer."
The notice, sent by Tarpley Shop Utility District, warned neighbors about haloacetic acids, a disinfectant byproduct of chlorinating the water.
The federal limit, or the maximum contaminant level, for haloacetic acids is 60 parts per billion, according to the EPA.
The letter from Tarpley Shop Utility District stated water from Jackson's area tested at 70 parts per billion between Oct. 1, 2016 and Sept. 30, 2017.
The letter stated residents do not need to boil their water or take other actions.
"However, if you have specific health concerns, consult your doctor," the notice read.
"No, it doesn't make me feel good," Jackson said. "That's all I think about."
Previous notices stated the value of haloacetic acids tested at 70 ppb as early as April 1, 2016.
"That would concern me. It's over the legal limit, and it's greatly elevated with respect to a level we think is a goal level," said David Andrews, a senior scientist with the nonprofit organization, Environmental Working Group.
Andrews said EWG supports dropping the federal limit for haloacetic acids even below the current standard of 60 ppb.
In 2017, 23 different utility districts in Tennessee violated that standard, according to Kim Schofinski, a spokeswoman for the Tennessee Department of Environment and Conservation.
More than half of those locations are in Middle Tennessee.
State records show Tarpley Shop Utility District reduced its levels of haloacetic acids to 61 ppb by the end of October 2017.
Compare that to Chanute-Pall Mall Utility District in Fentress County, which registered at 91 ppb during the same quarter.
The News 4 I-Team was unable to reach Chanute-Pall Mall Utility District Thursday afternoon.
Tarpley Shop serves roughly 2,500 customers, but the district only serves as a distribution site. The City of Pulaski treats the water before selling it to various utility districts in Giles County.
"How does it make you feel to know these residents could be put at a risk of getting sick?" asked reporter Alanna Autler.
"It is something that concerns us," said Anthony Bledsoe, the chief plant operator at the City of Pulaski. "We work with TDEC, we work within the guidelines they set for us, we use their approaches."
Some changes underway include aggressively flushing the water, reducing chlorine dosages, and putting mixers in storage tanks to circulate the water.
Bledsoe said since 2016, the city treatment plant has reduced the levels of haloacetic acids by 30 percent.
"If haloacetic acid is present in your tap water at the Federal limit (60 ppb), your risk of getting cancer from it is 1 in 10,000," read a statement from the City of Pulaski.
"The language says people who drink this water may have an increased risk of cancer," Bledsoe said. "The key word is, 'may.'"
"Is that word, 'may,' something you want to gamble on?" Autler asked.
"No, it's not," Bledsoe said. "But I do drink the water. I feel like our product is very, very good."
Jackson said as long as she continues to receive notices in the mail, she'll continue to worry.
"I'm not happy about it," Jackson said. "I'm not happy about drinking it, bathing in it, showering in it, giving it to my animals, but not being happy about it, there's nothing I can really do."
Schofinski said Tarpley Shop Utility District met state requirements after it faced enforcement actions last year. TDEC issued the district a civil penalty amounting to $4,480.
Over the past two years, TDEC has levied more than $125,000 in civil penalties against utility districts for issues related to haloacetic acids, according to a state enforcement database.
Monitoring results for the first quarter of 2018 have yet to be released.
At the end of 2017, 10 districts remained out of compliance, according to Schofinski. Those districts include:
Byrdstown Water Department
North Stewart Utility District
Tarpley Shop Utility District
Spencer Water System
Chanute-Pall Mall Utility District
Chemours-New Johnsville Plant
North Greene Utility
West Warren Utility District
Lobelville Water Department
Lynnville Water Department