2023 WQCCR - FINAL

Abbreviations: mS/cm = microsiemens N/A = not applicable ND = not detectable at testing limit

NTU = Nephelometric Turbidity Units TON = Threshold Odor Number TDS = Total Dissolved Solids UCMR = Unregulated Contaminant Monitoring Rules Umho/cm = micromhos per centimeter

ppt = parts per trillion TT = Treatment Techniques AL = Action Level NL = Notification Level pCi/L = picocuries per liter (a measure of radiation)

ppb = parts per billion or micrograms per liter ppm = parts per million or milligrams per liter

Chino Hills Water System

State MCL [MRDL]

Range and Average

Parameters [units]

PHG [MCLG]

Typical Source of Contaminant

Chino Hills Wells

Chino 1 Desalter

Monte Vista Water

REGULATED CONTAMINANTS WITH PRIMARY DRINKING WATER STANDARDS

RADIOACTIVE CONTAMINANTS, Sampled 2022-2023

Range

N/A

N/A

ND - 8

Gross Alpha [pCi/L]

15

[0]

Erosion of natural deposits

Average

N/A

N/A

2.5

Range

N/A

N/A

ND - 2.1

Uranium [pCi/L]

20

0.43

Erosion of natural deposits

Average

N/A

N/A

ND

Footnotes: * Trihalomethanes and Haloacetic Acids are a collection of sample results taken throughout the City from imported and blended water as a blended supply of all water. Average is highest location running annual average. * Lead and Copper samples are taken from residential household plumbing. *The State Water Resources Control Board considers 50 pCi/L to be the level of concern for beta particles. *Aluminum has both primary and secondary standards. The City’s 2023 UCMR 5 samples were ND. The Water Quality table lists all drinking water contaminants that were detected during the 2023 calendar year. The presence of the contaminants in the water does not necessarily indicate that the water poses or did pose a health risk. Unless otherwise noted, the data presented in this table is from testing conducted January 1, 2023 through December 31, 2023. The State allows us to monitor for some contaminants less than once per year because the concentrations of these contaminants do not change frequently. Some of our data, though representative, is more than one year old.

Special Note to Persons with Compromised Immune Systems Some people may be more vulnerable to contaminants in drinking water than the general population. Immune-compromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. U.S. EPA and Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline at 1 (800) 426-4791. The Federal Safe Drinking Water Act of 1974, and its 1986 amendment, are intended to ensure the quality of our nation’s water supplies. In order to ensure that tap water is safe to drink, the U.S. EPA and the SWRCB prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. How Safe Drinking Water Levels are Set