SALISBURY — A slight drop in the measured amount of total organic carbon or TOC removed from raw water from the Yadkin River by Salisbury Rowan Utilities (SRU) triggered an automatic notification of a violation to all customers, but a city spokesperson said today the water is still safe to drink.

According to the city, “state and federal regulations require SRU to notify all customers when a drinking water standard is not met, even if the situation has already been resolved.”

The Environmental Protection Agency (EPA) and the state set water quality standards, part of which require that levels of naturally organic carbon be maintained at a particular point. The level is measured by the amount of carbon being removed from the “raw” water. TOC stands for Total Organic Carbon, and that carbon comes from nature, such as soil and minerals. Some level of organic carbon is in almost all drinking water, even bottled water.

From Oct. 1, 2022, through Dec. 31, 2022, test results showed the treatment techniques dropped to 0.99 from the minimum of 1.0, causing SRU to receive a violation from the state.

SRU staff improved the treatment process on Sunday, Jan. 8, so that more carbon was removed. A follow-up sample was collected showing an adequate removal ratio of 1.07.

“Salisbury-Rowan Utilities tap water is safe to drink and is currently meeting all State and Federal water quality standards,” said SRU Director Jim Behmer. “SRU will continue monitoring water quality as directed by the North Carolina Department of Environmental Quality.”

“There’s a specific calculation we have to use that compares the average amount of carbon in the raw water to the average amount of carbon in drinking water after it’s treated,” city officials said Sunday, “and this gives us a ‘removal ratio.’ To be in compliance with water quality rules, we have to have a removal ratio of at least 1.0. Unfortunately, our removal ratio dropped to 0.99 so the state had to give us a violation for not meeting the goal of 1.

This is the first violation SRU has received. Everyone who is an SRU customer, whether they live in Salisbury or not, will have received the required notification.

Officials say “organic carbon doesn’t cause any health effects. The reason we reduce the amount of TOC in water is because it can interact with chlorine (used to disinfect the water) and form something called ‘disinfection byproducts'” which, in concentrated amounts, can cause health problems.

A full explanation of the details of the violation and the requirements can be found on the city’s website where Frequently Asked Questions are listed here.

Because the TOC levels are tested in raw water, then compared to the treated water at the source, testing water in individual homes will not provide information on the removal levels. But residents can see test results by viewing the city’s annual Consumer Confidence Report; it is available online at https://salisburync.gov/waterreport.