The sources of drinking water (both tap water and bottled water) include oceans, rivers, lakes, streams, ponds, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, pick up substances resulting from the presence of animals or from human activity.

Contaminants that may be present in source water include:

• Microbial contaminants, such as viruses and bacteria that can come from wastewater treatment plants, septic systems, agricultural livestock operations and wildlife.
• Inorganic contaminants, such as salts and metals, that can be naturally occurring or result from urban storm water runoff, industrial or domestic wastewater discharges, oil and gas production, mining or farming.

• Pesticides and herbicides, that can come from a variety of sources such as agriculture, urban stormwater runoff and residential uses.

• Organic chemical contaminants, including synthetic and volatile organic chemicals, that are byproducts of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff,

agricultural application and septic systems.

• Radioactive contaminants, that can be naturally occurring or be the result of oil and gas production and mining activities.

How to read this report

As you read the water quality tables in this report, compare the level of contaminants found in CMWD’s water in the “Skinner Plant”, “Twin Oaks Valley Plant”, and “Desal plant” columns with the standards set for them in the MCL and PHG columns. The CMWD met all drinking water standards in 2019.

The following are key terms to help you understand the standards used to measure drinking water safety.

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. Secondary MCLs are set to protect the odor, taste and appearance of drinking water.

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 the U.S. Environmental Protection Agency.

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.

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.

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.

Primary Drinking Water Standard (PDWS) MCLs and MRDLs for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements.

Treatment Techniqud A required process intended to reduce the level of a contaminant in drinking water.

Regulatory Action Level The concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.

This report can be downloaded from

www.carlsbadca.gov/water-quality-report

Abbreviations

14. Nitrogen

46. Treatment Technique is a required process intended to reduce the level of a contaminant in drinking water

Required information for lead

If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. CMWD is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking. If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water, testing methods and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline or at www.epa.gov/safewater/lead. CMWD has complied and meets Lead and Copper standards.

Footnotes

1. (Skinner) As a Primary Standard, the turbidity levels of the filtered water were < 0.3 NTU in 95% of the online measurements taken each month and did not exceed 1 NTU for more than one hour.
   The turbidity levels for grab samples at these locations were in compliance with the Secondary Standard. (Twin Oaks) The turbidity level from the CFE of the membranes shall be < 0.1 NTU in 95% of the measurements taken each month and shall not exceed 1.0 NTU at any time. Turbidity, a measure of the cloudiness of water, is an indicator of treatment performance.
2. Total coliform MCLs: No more than 5% of the monthly samples may be total coliform positive. Compliance is based on the combined distribution system sampling. In 2020, 1,560 samples were analyzed with no positive samples. The MCL was not violated.
3. E. coli MCL: The occurrence of two consecutive total coliform- positive samples, one of which contains E. coli, constitutes an acute MCL violation. The MCL was not violated.
4. Skinner and Twin Oaks were in compliance with all provisions of the State’s Fluoridation System Requirements.
5. Lead and copper are regulated by Action Levels under the Lead and Copper Rule, which requires water samples to be collected at the consumers’ tap. If action levels are exceeded in more than 10% of the samples, water systems must take steps to reduce these contaminants.
6. Twin Oaks/Skinner met all provisions of the Stage 1 Disinfectants/ Disinfection By-Products (D/DBP) Rule. Compliance was based on Locational RAA. Average and range for the treatment plant effluent were taken from daily and monthly samples for TTHM and HAA5.
7. Twin Oaks running annual average was calculated from quarterly results of monthly and daily samples. Bromate reporting level is 4.2 ppb.
8. Chromium VI reporting level is ND, which is below the state DLR of 1 ppb.
9. AI <10.0 = Highly aggressive and very corrosive water.
   AI >12.0 = Non-aggressive water. AI (0.14 – 13.0) = Moderately aggressive water.
10. Positive SI index = non-corrosive; tendency to precipitate and/or deposit scale on pipes. Negative SI index = corrosive; tendency to dissolve calcium carbonate.

The U.S. Environmental Protection Agency and the State Water Resources Control Board have regulations that limit the amount of certain contaminants allowed in water provided by public water systems to ensure that tap water is safe to drink. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the U.S. EPA’s Safe Drinking Water Hotline at 800-426-4791.

CMWD has sampled all required data including entry points in the distribution system for the fourth Unregulated Contaminant Monitoring Rule (UCMR 4) contaminants in 2020. The analytical results for UCMR

4 are stored in the National Contaminant Occurrence Database for drinking water, which can be found online at www.epa.gov/sdwa/national- contaminant-occurrence-database-ncod.

Water conservation

Carlsbad encourages residents and businesses to continue making water conservation a way of life. With water being a precious and limited resource, Carlsbad is doing our part by making water conservation and the efficient use of water a major priority. Even the simplest changes to daily routines make a difference.

Do your part by following the water conservation tips below, and visit www.carlsbadca.gov/conservation for programs, incentives, water rules, and more tips and resources.

Indoor

• Take short showers or fill the bathtub halfway
• Turn water off when brushing teeth or shaving
• Wash only full loads of clothes
• Fix leaks (toilets, faucets, etc.)
• Install high-efficiency fixtures

Outdoor

• Install drip-irrigation
• Adjust sprinklers to reduce water lost from overspray onto impervious surfaces
• Water during cool parts of the day to reduce evaporation
• Install a smart irrigation controller
• Convert to a native landscape
• Repair broken sprinkler heads and/or irrigation lines (do not irrigate until repair is made)

How to contact us

This report covers testing for contaminants in 2018. For questions or concerns regarding the quality of Carlsbad’s drinking water, contact the

CMWD at 760-438-2722 or email water@carlsbadca.gov.

CMWD Board meetings are held in conjunction with the Carlsbad City Council on an as needed basis on Tuesday

evenings. Agendas may be obtained

at www.carlsbadca.gov or Carlsbad City Hall, 1200 Carlsbad Village Drive. Comments regarding drinking water are always welcome by the CMWD Board of Directors.

This report can be downloaded from www.carlsbadca.gov/water-quality-report.

Carlsbad Municipal Water District

5950 El Camino Real, Carlsbad, CA 92008 Hours: Monday through Friday, 8 a.m. to 5 p.m. 760-438-2722 • water@carlsbadca.gov

Additional sources for water quality information:

San Diego County Water Authority 858-522-6600 • www.sdcwa.org

Metropolitan Water District of Southern California

800-CALL-MWD (225-5693) www.mwdh2o.com

State Water Resources Control Board Division of Drinking Water & Environmental Management 619-525-4159 www.waterboards.ca.gov

U.S. Environmental Protection Agency Office of Ground Water & Drinking Water Safe Drinking Water Hotline 800-426-4791 www.epa.gov/watersense/state-water-facts