Response to EWG Water Quality Report
Charlotte Water has reviewed the information presented by the Environmental Working Group (EWG). We are disappointed that the EWG has elected to display the information in this manner. The website implies that Charlotte Water provides something less than a clean, safe and reliable source of drinking water for the Charlotte community.
Charlotte Water’s goal is to first provide the highest quality drinking water to customers and second meet all regulatory standards. All test results are reported to the State of North Carolina and posted on Charlotte Water’s website for the public to review. Charlotte Water’s state-of-the-art treatment program is routinely recognized and awarded for the quality of water produced. Treatment processes successfully manage corrosion of metals such as lead and copper and drive down organic materials to control disinfection byproducts. Continuous monitoring of water quality from the source to the tap assures the effectiveness of the treatment processes. Charlotte Water maintains a network of more than 4,200 miles of pressurized pipes delivering water to homes and businesses 24/7.
The quality of Charlotte’s drinking water and the health and safety implications to our community are too serious to misrepresent. We encourage the public to review the data for themselves, understand the information and ask Charlotte Water any questions about our services.
Information related specifically to the EWG report
- Seven of the eight constituents referenced by the EWG as a concern are Disinfection Byproducts (DBPs) and reflect results from 2015 monitoring. Disinfection byproducts are formed when temperatures are high, pH is high and organics are present. There was an upward trend in DBPs in 2015 due to elevated bromide levels in our source (untreated) water which we wrote about and conducted a press conference. As soon as the trend was discovered Charlotte Water took swift action to notify the public, locate the source of upward trend, work to remove the impact and simultaneously manage the water quality provided to customers to keep them safe.
- In order to achieve compliance with the EPA’s Stage II DBP Rule, the locational running annual average (LRAA) of each monitoring location sampled within Charlotte Water’s distribution system must be less than 80 ppb THM and 60 ppb HAA. Charlotte Water is well within those water quality requirements. Currently, Charlotte Water’s highest THM LRAA is 47.9 ppb while the highest HAA LRAA is 12.3 ppb.
- Our treatment process is designed to first reduce the concentration of organic material in the source water, measured as total organic carbon (TOC), and followed by disinfection utilizing chlorine. Natural organic material is a primary precursor for the formation of THMs when chlorine is utilized for disinfection. Placing chlorination after organics removal in the treatment process results in less available organic material for chlorine to react with and limits the formation potential of THMs. Other factors such as temperature and water age also play a significant role in the formation of THMs, with higher temperatures and longer water age resulting in higher THM concentrations. Because Charlotte Water’s distribution system is so vast with over 4200 miles of pipeline, programmable flushing devices are utilized throughout the system to reduce water age. In addition, elevated storage tanks are operated at lower levels during the summer months.
- Charlotte Water supplies drinking water that has gone through a 6-stage treatment process to ensure the highest quality.
- Every residential customer in Mecklenburg County received the 2016 Drinking Water Quality report by mail in June 2017. A list of water quality parameters that were not detected in Charlotte’s drinking water is on the Charlotte Water website.
- The EWG website cites information that is incorrect. Charlotte Water has not had any water quality violations in this time period. Charlotte Water never exceeded the THM/HAA LRAA limits during the timeframe referenced below. In fact, no individual data point exceeded the 80/60 levels for either constituent during this period (4th Qtr 2014, 1st Qtr 2015 and 2nd Qtr 2015). Follow up conversation with State regulators today confirms this information. A website glitch is the best explanation for the information the EWG cited. We’ve encountered this recently with both the State and EPA websites displaying incorrect information and then Charlotte Water has to make the accurate information available.
- The EWG report compares reported results for Safe Drinking Water Act compliance to the California Office of Environmental Health Hazard Assessment’s health guidelines for some contaminants. These health guidelines are not regulatory standards but are specific to California and the requirements for setting drinking water standards in that state. There are no established health guidelines for drinking water quality in North Carolina other than what is required by the Safe Drinking Water Act which is regulated by EPA and the NC Department of Environmental Quality.