2022 Public Health Goals Report on Drinking WaterPresented by:The City of Rialto / Rialto Utility Authority
WHAT ARE PUBLIC HEALTH GOALS (PHGS)?PHG is the safe level of concentration which poses no significant health risk if consumed for a lifetime. The process of establishing a PHG is a risk assessment based strictly on human health considerations. PHGs are recommended targets and are not required to be met by any public water system.PHGs are developed by the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment.
What is Maximum Contaminant Level?Upon establishment of a PHG, the California State Water Resources Control Board Division of Drinking Water and Environmental Management (SWRCB) determines a Maximum Contaminant Level (MCL) in drinking water. The MCL is the highest level of concentration that is allowedin drinking water for a contaminant.
The 2022 PHGs Report Detected One Contaminant Above the Public Health guidelines:ARSENIC What is ARSENIC?•Arsenicis a semi-metal element in the periodic table. It is a naturally occurring element that is found in combination with either inorganic or organic substances, and are found in soils, sediment, and sand groundwater.•The Public Health Goal (PHG) for arsenic in drinking water is 0.004 ppb (parts per billion). •The Maximum Contaminant Level (MCL) for arsenic is 10 ppb. •Therefore, safelevels of arsenic in drinking water is any level under 10ppb, zero being the safest.•Arsenic was found to occur in only one groundwater well – City Well 2, and not in any other wells.•It should be noted that City Well 2 water is blended with additional water sources that contain no detection levels of arsenic.
FACTS!SAFELEVELS OF ARSENIC HAS BEEN DETECTED IN OUR DRINKING WATER SINCE SAMPLING HAS BEEN REQUIRED.
Detection Levels
Arsenic was found to occur in one groundwater well, City Well 2, with a detection of 3.1ppb, which is within the safety zone of 0 – 10bbp.
Arsenic was found to occur in one groundwater well, City Well 2, with a detection of 3.1ppb, which is within the safety zone of 0 – 10bbp.
Keep in mind, 3.1 ppb was the highest arsenic level detected at one point in time amongst multiple tests performed throughout the year.
Keep in mind, 3.1 ppb was the highest arsenic level detected at one point in time amongst multiple tests performed throughout the year.
The averagearsenic detection level for 2021 was only .52 ppb, which is very close to the PHGs level of .004.
The averagearsenic detection level for 2021 was only .52 ppb, which is very close to the PHGs level of .004. 7-YEAR COMPARISON – Highest-Point Arsenic Level:Over the past 7 years, thehighest arsenic leveldetected dropped from 4.7 ppb in 2015 to3.1 ppb in 2021, resulting in a 34% decrease:
7-YEAR COMPARISON – Average Arsenic Level:During the same period, the average arsenic levelhas dropped from 2.8 ppb in 2015 to .52 ppb in 2021, resulting in an 81% decrease:
PROGRESSION TO “NO DETECTION”Overall, the amounts of Arsenic detected between 2015 and 2021 has dropped each year since 2015 and is making progress to a “No Detection”Arsenic level result in future PHGs reporting. The state does not require treatment when the contaminant level is less than 50% of the MCL.Currently, the State only requires 1 test per 3 years, which is less frequent than others which require more sampling and testing.
THE ENDThe 2022 edition of the Public Health Goals Report is included as Attachment 1.The 2021 Consumer Confidence Report (CCR) is included as Attachment 2.