Important Information About Your Drinking Water

Important Update About Your Drinking Water: Average Levels of Haloacetic Acids (HAA5) in Small, Affected Area of Kernville Water System Decreased in Third Quarter 2019

Dear California Water Service (Cal Water) Customer:

The Kernville water system is required to test water quality samples collected from the distribution system at two Division of Drinking Water (DDW) approved sites [107 Juniper and 1235 Sycamore] for HAA5 each quarter. HAA5 has a Maximum Contaminant Level (MCL) of 60 ug/L (parts per billion), which is calculated through a Locational Running Annual Average (LRAA). The LRAA is an average over 4 consecutive quarters. Water quality testing at 107 Juniper in the third quarter of 2019 resulted in a LRAA of 61 ug/L for HAA5,which is slightly above the MCL. The LRAA at 1235 Sycamore was 8 ug/L.

Samples collected during the third quarter of 2019 at 107 Juniper had detections of HAA5 that averaged 50 ug/L, which is lower than in the previous quarter and, by itself, is below the limit. Residents living on Oak Court, Oak Place, Juniper Drive, Alder Court, and Grandview in Kernville are in the same zone as 107 Juniper and, therefore, have similar water quality. Testing at this location affects about 50 customers. Please see the attached map for more precise details about the area within our Kernville system. The samples taken at 1235 Sycamore had a third quarter average of 9.5 ug/L.


We closely monitor our water system for the presence of drinking water contaminants. The Kernville water system uses the Kern River as its water source. In 2016, 2017, and 2019, runoff from winter storms contributed to higher levels of total organic carbon (TOC) material in the Kern River supply. In the most recent quarter, the Kern River had a drop in runoff and, therefore, a drop in TOC levels. The presence of TOC creates a treatment challenge in our state-of-the-art surface water treatment plant. Higher than normal TOC levels, along with chlorine from our disinfection process, contribute to the formation of disinfection byproducts, which are measured as HAA5 and total trihalomethanes (TTHM).

Some people who drink water containing HAA5 in excess of the MCL over many years may have an increased risk of cancer. If you have other health issues concerning the consumption of this water, you may wish to consult your doctor.

Protecting your health and safety is our highest priority. Upon receiving the first high result in February 2016, we immediately began making operational changes in the water treatment plant and water distribution system to reduce HAA5. These changes included adjusting the amount of disinfection used to effectively treat the water and modifying storage tank levels to encourage turnover and decrease water aging in the system. State-mandated reductions in water use during the historic drought increased the aging of water in the distribution system.

To improve the water quality long-term, we are in the process of installing a two-vessel granular-activated carbon (GAC) treatment system at the Kernville surface water treatment plant. The purpose of this treatment is to remove TOC from the water before it enters the distribution system, as confirmed by the pilot treatment system installed in 2017. We expect the GAC treatment system to be fully operational by the end of 2019, and to see a reduction in the HAA5 levels once the treatment system is fully operational.

We will continue to work diligently to maintain water quality. This letter serves as notification in accordance with Title 22 of the California Code of Regulations. For more information, please contact our local Cal Water Customer Center at (760) 379-5336.

Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses). You can do this by posting this public notice in a public place or distributing copies by hand or mail.

Secondary Notification Requirements

Upon receipt of notification from a person operating a public water system, the following notification must be given within 10 days [Health and Safety Code Section 116450(g)]:

  • SCHOOLS: Must notify school employees, students, and parents (if the students are minors).
  • RESIDENTIAL RENTAL PROPERTY OWNERS OR MANAGERS (including nursing homes and care facilities): Must notify tenants.
  • BUSINESS PROPERTY OWNERS, MANAGERS, OR OPERATORS: Must notify employees of businesses located on the property.
  • You can do this by posting this public notice in a public place or distributing copies by hand or mail. This notice is being sent to you by California Water Service’s Kernville system.

State Water System ID#: 1510033
Date distributed: October 10, 2019