Press Release

Operational Changes Reduce Disinfection Byproduct Levels in Portion of Kernville System

Fifty Kernville customers impacted by water system issue

LAKE ISABELLA, Calif.— Operational changes made in California Water Service's (Cal Water) Kernville water system have begun to successfully decrease levels of haloacetic acids (HAA5) in water serving a small portion of the Kernville system. Cal Water has been working with the State Water Resources Control Board's Division of Drinking Water (DDW) to reduce recently elevated levels of the disinfection byproduct.

Runoff from winter storms in early 2016 contributed to higher levels of naturally occurring total organic carbon (TOC) material in the Kern River water supply. Higher TOC levels contribute to the formation of disinfection byproducts during the treatment process, which is necessary to meet federal and state water quality standards, according to Local Manager Chris Whitley.

Compliance with the HAA5 standard is based on a running annual average of samples collected each quarter at dedicated sampling sites. The most recent water quality test samples collected in the second quarter of 2016 at one Cal Water sampling site were under the maximum contaminant level (MCL) of 60 parts per billion. Due to higher test results at the site in the first quarter of 2016, however, the average result over the past 12 months is over the MCL at 87.8 ppb.

According to Whitley, this is not an immediate health risk for the 50 customers in the affected area, but rather a concern when consuming water at levels above the MCL over many years. The affected area includes Oak Court, Oak Place, Juniper Drive, Alder Court, and Grandview in Kernville. Water quality tests confirm that HAA5 levels for all other areas within the Kern River Valley District remain in compliance with the MCL.

To lower the HAA5 levels, Cal Water crews have taken a multi-pronged approach in both the treatment plant and the distribution system. Crews have adjusted the amount of disinfection used, modified storage tank levels to encourage turnover and decrease water aging in the system, and installed a pilot granular-activated carbon treatment unit to remove the TOC, which is expected to go online in the coming months. Additionally, TOC levels in the Kern River are returning to the normal range, which will decrease the potential for HAA5 formation.

"At Cal Water, protecting our customers' health and safety is our highest priority," Whitley said. "We monitor the system very closely and are dedicated to resolving this issue. We are seeing steady improvement and will keep moving forward with these operational changes to bring the annual average of levels, which had been elevated due to stormwater runoff and water quality treatment, back into compliance."

Cal Water serves approximately 4,300 service connections in the Kern River Valley and about 2 million people through 480,300 service connections in California. The company, which has provided water service in the area since 2000, was ranked "Highest in Customer Satisfaction among Water Utilities in the West" in 2016 by J.D. Power in its inaugural Water Utility Residential Customer Satisfaction Study. Additional information may be obtained online at