2023 Irvine Ranch Water District Distribution System Water Quality
MCL
Average Amount
Range of Detections 11.4 – 57.7 6.2 – 42.8
MCL
Typical Source of Contaminant
Disinfection Byproducts
(MRDL/MRDLG)
Violation?
Total Trihalomethanes (ppb) Haloacetic Acids (five) (ppb) Chlorine Residual (ppm)
80 60
30.2*** 19.0***
No No No
Byproducts of Chlorine Disinfection Byproducts of Chlorine Disinfection Disinfectant Added for Treatment
(4.0 / 4)
1.7
ND – 4.8
Aesthetic Quality Color (color units)
15*
<3
ND – 7 ND – 15 ND – 3
No No No
Erosion of Natural Deposits Erosion of Natural Deposits Erosion of Natural Deposits
Turbidity (NTU)
5* 3*
0.12
Odor (threshold odor number)
<1
Other Fluoride (mg/L)
2 / 0.8**
0.51
0.23 – 0.82
No
Erosion of Natural Deposits, Water Treatment
Twelve locations in the distribution system are tested quarterly for total trihalomethanes and haloacetic acids; 60 locations are tested monthly for color and odor, and weekly for chlorine residual and turbidity.
MRDL = Maximum Residual Disinfectant Level; MRDLG = Maximum Residual Disinfectant Level Goal
*Contaminant is regulated by a secondary standard
**MCL/Optimum Level for our climate
***Highest running annual average at any individual sample location.
Lead and Copper Action Levels at Residential Taps
90 th
Action Level
Public Health
Sites Exceeding AL /
AL
Typical Source of Contaminant
(AL)
Goal (PHG)
Percentile Value
Number of Sites
Violation
Copper (ppm)
1.3
0.3 0.2
0.1908
0 / 72 0 / 72
No No
Corrosion of Household Plumbing Corrosion of Household Plumbing
Lead (ppb)
15
<5
The most recent lead and copper at-the-tap samples were collected from 72 residences in 2022. Lead was detected in 0 homes and copper was detected in 26 homes, but none of the samples for lead and copper exceeded the respective regulatory Action Level (AL). A regulatory Action Level is the concentration of a contaminant which, if exceeded in more than 10% of samples, triggers treatment or other requirements that a water system must follow.
Unregulated Chemicals Requiring Monitoring in the Distribution System
Chemical
Notification Level
PHG (MCLG)
Average Local and Imported
Range of Detections
Most Recent Sampling Date
Germanium, Total (ppb) Manganese, Total (ppb)
n/a
n/a n/a n/a n/a n/a n/a
0.82
ND – 1.1 0.8 – 2.2 1.5 – 13 0.6 – 3.8 0.4 – 2.5 0.9 – 7.0 1.7 – 25 ND – 1.2 ND – 3.8 ND – 10
2020 2020 2019 2019 2019 2019 2019 2019 2019 2019
MCL = 50*
1.6 3.9 1.3 1.0 2.5 4.9 0.3 0.2 1.3
Bromochloroacetic Acid (ppb) Bromodichloroacetic Acid (ppb) Chlorodibromoacetic Acid (ppb) Dibromoacetic Acid (ppb) Dichloroacetic Acid (ppb) Monobromoacetic Acid (ppb) Monochloroacetic Acid (ppb)
n/a n/a n/a n/a n/a n/a n/a n/a
(0)
n/a
(70) (20)
Trichloroacetic Acid (ppb)
*Contaminant is regulated by a secondary standard
Chart legend What are water quality standards?
What is a water quality goal? In addition to mandatory water quality standards, U.S. EPA and DDW have set voluntary water quality goals for some contaminants. Water quality goals are often set at such low levels that they are not achievable in practice and are not directly measurable. Nevertheless, these goals provide useful guideposts and direction for water management practices. The chart in this report includes three types of water quality goals: • Maximum Contaminant Level Goal (MCLG): The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are set by U.S. EPA. • Maximum Residual Disinfectant Level Goal (MRDLG): The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants. • Public Health Goal (PHG): The level of a contaminant in drinking water below which there is no known or expected risk to health. PHGs are set by the California Environmental Protection Agency. How are contaminants measured? Water is sampled and tested throughout the year. Contaminants are measured in:
Drinking water standards established by U.S. EPA and DDW set limits for substances that may affect consumer health or aesthetic qualities of drinking water. The chart in this report shows the following types of water quality standards: • Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. Primary MCLs are set as close to the PHGs (or MCLGs) as is economically and technologically feasible. • Maximum Residual Disinfectant Level (MRDL): The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants. • Secondary MCLs are set to protect the odor, taste, and appearance of drinking water. • Primary Drinking Water Standard: MCLs for contaminants that affect health along with their monitoring and reporting requirements and water treatment requirements. • Regulatory Action Level (AL): The concentration of a contaminant, which, if exceeded, triggers treatment or other requirements that a water system must follow.
• Parts per million (ppm) or milligrams per liter (mg/L) • Parts per billion (ppb) or micrograms per liter ( µ g/L) • Parts per trillion (ppt) or nanograms per liter (ng/L)
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