2019 Consumer Confidence Report
on Water Quality for 2018

people using water

Golden State Water Company (Golden State Water) is pleased to present our 2019 Annual Water Quality Report (Consumer Confidence Report), providing customers with important information regarding local water quality and service during the 2018 calendar year.

Golden State Water is proud to report that the water delivered to your tap continues to meet all federal and state quality standards established to protect public health and safety. Within this document, you will find information regarding local water supply sources, testing and the steps Golden State Water takes to ensure our water is in compliance with standards set by the United States Environmental Protection Agency (USEPA), State Water Resources Control Board’s (State Board) Division of Drinking Water and California Public Utilities Commission (CPUC).

For more than 90 years, Golden State Water has been committed to providing high-quality water and reliable service throughout California. Delivering drinking water is serious business, and our team of scientists, engineers and water experts is dedicated to protecting our water systems and ensuring the water we deliver to local homes and businesses meets the stringent standards set by the state and federal governments and is safe to drink.

Golden State Water provides water service to approximately 1 million customers in more than 80 communities throughout California. We aggressively monitor and test for hundreds of contaminants in each of our 37 water systems and have consistently scored among the top water companies for compliance with water quality regulations.

To access the most up-to-date Water Quality Report for your area, sampling results and to learn more about common contaminants, you can visit www.gswater.com/water-quality/. If you have any questions about this report, please contact our 24-hour Customer Service Center at 1.800.999.4033 or email us at customerservice@gswater.com.

Golden State Water is constantly working toward 100 percent customer satisfaction and encourages all customers to visit
www.gswater.com and follow us on Twitter and on Facebook at @GoldenStateH2O.

On behalf of everyone at Golden State Water, thank you for allowing us the opportunity to serve you and your family.


Robert Sprowls
President and Chief Executive Officer
Golden State Water Company

Richard Mathis
General Manager, Central District
Golden State Water Company

Where does my water come from?

Cross Connection Control Program

Conserving for California

Hydrant Flushing

Glossary of Terms

Connect with us to learn more!


Risk to Tap and Bottled Water

Source and Distribution Water Quality

For People with Sensitive Immune Systems

Source Water Assessment

About the Company

Laboratory Analysis

Printed report

Top priority

If You Have Questions – Contact Us

For information about your water quality or to find out about upcoming opportunities to participate in public meetings, please contact our 24-hour Customer Service Center at 1.800.999.4033. Visit us online at www.gswater.com or email us at customerservice@gswater.com.

Este informe contiene información muy importante sobre su agua de beber. Tradúzcalo o hable con alguien que lo entienda bien.

Conserving for California

The 2018-19 winter season has provided an abundance of rain and snow for most of California, and water supply sources in many regions have recharged to normal levels. Although winter storms arrived a little late in the season, the state’s snowpack water content measured at record levels in March 2019.

While water supply conditions have improved for a large part of the state, sources in some regions have yet to recharge to historical norms and communities continue to struggle with supply insecurity.

Golden State Water Company reminds customers that California is a drought-prone state, and there is no certainty that we will experience wet winters in the years to come. We must continue to use water responsibly to protect against and prepare for future droughts. It’s important that we all work together to make conservation a part of our daily lives.

State law prohibits actions that result in water waste, such as hosing off driveways and sidewalks, washing a motor vehicle with a hose without a shut-off nozzle, watering outdoor landscapes that causes excess runoff, operating decorative fountains that do not recirculate water, and watering ornamental turf or public street medians.

Golden State Water thanks you for your conservation efforts. To learn more about conservation programs and/or water-use restrictions in your area, please visit www.gswater.com or call 1.800.999.4033.

desert and coastal drought tolerant landscaping
Examples of desert and coastal drought tolerant landscaping.

Where Does My Water Come From?

Water delivered to customers in the Norwalk System is a blend of groundwater pumped from the Central Groundwater Basin and imported water from the Colorado River Aqueduct and the State Water Project (imported and distributed by the Metropolitan Water District of Southern California). The Central Groundwater Basin is bounded on the north by the La Brea Uplift; on the east by the Elysian, Repetto, Merced and Puente hills; on the southeast by the Orange County Groundwater Basin; and on the west by the Newport-Inglewood Fault Zone.

Glossary of Terms

Maximum Contaminant Level (MCL)
The highest level of a contaminant that is allowed in drinking water. Primary MCLs are set as close to the public health goals and maximum contaminant level goals as is economically and technologically feasible. Secondary MCLs are set to protect the odor, taste and appearance of drinking water.

California Notification Level (NL)
Non-regulatory, health-based advisory levels established by the State Board for contaminants in drinking water for which an MCL has not been established.

Maximum Contaminant Level Goal (MCLG)
The level of contaminant in drinking water below which there is no known or expected risk to health. Maximum contaminant level goals are set by the United States Environmental Protection Agency (USEPA).

Maximum Residual Disinfectant Level (MRDL)
The highest level of a disinfectant allowed in drinking water. There is convincing evidence that the 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, MRDLs and treatment techniques (TTs) for contaminants that affect health, along with their monitoring and reporting requirements.

Public Health Goal (PHG)
The level of a contaminant in drinking water below which there is no known or expected risk to health. Public health goals are set by the California Environmental Protection Agency (CalEPA).

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

Treatment Technique (TT)
A required process intended to reduce the level of a contaminant in drinking water.


Contaminants are measured in Unit Abbreviation Also known as This can be compared to…
Parts per million (PPM) mg/L milligrams per liter 1 second in 12 days
Parts per billion (PPB) µg/L micrograms per liter 1 second in 32 years
Parts per trillion (PPT) ng/L nanograms per liter 1 second in 32,000 years
Grains per gallon grains/gallon a measurement for water hardness often used for sizing household water softeners 1 grain/gal equals 17.1 mg/L of hardness
Nephelometric Turbidity Units NTU a measurement of the clarity of water Turbidity in excess of 5 NTU is noticeable to the average person
Microsiemens per centimeter µS/cm a measurement of a solution’s ability to conduct electricity

Picocuries per liter pCi/L a measurement of radioactivity in water

Norwalk Water System – Source Water Quality
Primary Standards –
Health Based (units)
Range of
Most Recent
Sampling Date
Typical Source of Constituent
Highest single measurement of the treated surface water (NTU) TT = 1.0 n/a n/a 0.06 2018 Soil runoff
Lowest percent of all monthly readings less than 0.3 NTU (%) TT = 95 n/a n/a 100% 2018 Soil runoff
Inorganic Constituents
Aluminum (mg/L) 1 0.6 ND – 0.31 0.08 2018 Erosion of natural deposits; residue from some surface water treatment processes
Arsenic (µg/L) 10 0.004 ND – 3.8 ND 2018 Erosion of natural deposits; runoff from orchards, glass and electronics production wastes
Barium (mg/L) 1 2 ND – 0.14 ND 2018 Discharges of oil drilling wastes and from metal refineries; erosion of natural deposits
Fluoride (mg/L) (a) 2.0 1 0.3 – 1.0 0.7 2018 Erosion of natural deposits; water additive that promotes strong teeth; discharge from fertilizer and aluminum factories
Nitrate [as N] (mg/L) 10 10 ND – 8.4 3.1 2018 Runoff and leaching from fertilizer use; leaching from septic tanks and sewage; erosion of natural deposits
Selenium (µg/L) 50 30 ND – 15 ND 2018 Discharge from petroleum, glass, and metal refineries; erosion of natural deposits; discharge from mines and chemical manufacturers; runoff from livestock lots (feed additive)
Volatile Organic Constituents
1,1-Dichloroethane 5 3 ND – 1.5 ND 2018  
1,2-Dichlorethane (µg/L) 0.5 0 ND – 1.4 (b) ND 2018 Discharge from chemical plants and other industrial activities
Radioactive Constituents
Gross Alpha Activity (pCi/L) 15(c) (0) ND – 8 ND 2018 Erosion of natural deposits
Uranium (pCi/L) 20 0.43 ND – 7 3 2018 Erosion of natural deposits
Secondary Standards –
Aesthetic (units)
Range of
Most Recent
Sampling Date
Typical Source of Constituent
Aluminum (µg/L) 200 n/a ND – 310 76 2018 Erosion of natural deposits; residue from some surface water treatment processes
Color (units) 15 n/a ND – 1 1 2018 Naturally-occurring organic materials
Chloride (mg/L) 500 n/a 38 – 100 82 2018 Runoff/leaching from natural deposits; seawater influence
Iron (µg/L) 300 n/a ND – 140 ND 2018 Leaching from natural deposits; industrial wastes
Odor—Threshold (units) 3 n/a ND – 4 2 2018 Naturally-occurring organic materials
Specific Conductance (uS/cm) 1600 n/a 428 – 1500 960 2018 Substances that form ions when in water; seawater influence
Sulfate (mg/L) 500 n/a 39 – 330 180 2018 Runoff/leaching from natural deposits; industrial wastes
Total Dissolved Solids (mg/L) 1000 n/a 320 – 1000 610 2018 Runoff/leaching from natural deposits
Turbidity (NTU) 5 n/a 0.10 – 0.34 0.12 2018 Soil runoff
Other Parameters (units) Notification
PHG (MCLG) Range of Detection Average Level Most Recent Sampling Date Typical Source of Constituent
Alkalinity (mg/L) n/a n/a 68 – 300 200 2018  
Calcium (mg/L) n/a n/a 19 – 180 96 2018  
Hardness [as CaCO3] (mg/L) n/a n/a 84 – 600 330 2018 The sum of polyvalent cations present in the water, generally magnesium and calcium; the cations are usually naturally occurring
Hardness [as CaCO3] (grains/gal) n/a n/a 4.9 – 35 23 2018  
Magnesium (mg/L) n/a n/a 7.8 – 37 22 2018  
pH (pH units) n/a n/a 7.5 – 8.5 8.0 2018  
Potassium (mg/L) n/a n/a 2.4 – 5.5 4.4 2018  
Sodium (mg/L) n/a n/a 40 – 100 70 2018 Refers to the salt present in the water and is generally naturally occurring
Unregulated Drinking Water Constituents (units) Notification
Range of
Most Recent
Sampling Date
1,4-Dioxane (µg/L) 1 n/a 1.2 – 6.6 3.7 2017  
Vanadium (µg/L) 50 n/a ND – 3.2 ND 2014  
Molybdenum (µg/L) n/a n/a 1.4 – 5.0 2.3 2014  
Strontium (µg/L) n/a n/a 450 – 1200 760 2014  
Chlorate (µg/L) 800 n/a 39 – 250 137 2014  
Perfluorooctanesulfonic acid (PFOS) (µg/L) n/a n/a ND – 0.043 ND 2014  
Norwalk Water System – Distribution Water Quality
Constituents (units)
Value Most Recent
Sampling Date
Typical Source of Constituent
Total Coliform Bacteria ≥40 Samples/Month
(Present / Absent)
More than 5% of monthly samples are positive (0) Highest percent of monthly samples positive was 1.6% 2018 Naturally present in the environment
Disinfection Byproducts
and Disinfectant Residuals (units)
Range of
Average Level Most Recent
Sampling Date
Typical Source of Constituent
Bromate (µg/L) 10 0.1 ND – 10 4.1 2018 Byproduct of drinking water disinfection
Chlorine [as Cl2] (mg/L) (4.0) (4) 0.2 – 3 1.3 2018 Drinking water disinfectant added for treatment
HAA5 [Total of Five Haloacetic Acids] (µg/L) 60 n/a ND – 7.2 12 2018 Byproduct of drinking water disinfection
TTHMs [Total of Four Trihalomethanes] (µg/L) 80 n/a 9.1 – 41 38 2018 Byproduct of drinking water disinfection
Inorganic Constituents
90th %
Most Recent
Sampling Date
Typical Source of Constituent
Copper (mg/L) 1.3 0.3 None of the 36 samples collected exceeded the action level. 0.25 2016 Internal corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives
Lead sampling in schools and residential plumbing Action
PHG Sample
90th %
Most Recent
Sampling Date
Typical Source Number of Schools Tested(d)
Lead (µg/L) 15 0.2 None of the 36 samples collected exceeded the action level. ND 2016 Internal corrosion of household water plumbing systems; discharges from industrial manufacturerers; erosion of natural deposits. 11
(a) Our water system treats your water by adding fluoride to the naturally occurring level to help prevent dental caries in consumers. State regulations require the fluoride levels in the treated water to be maintained within a range of 0.6-1.2 mg/L with an optimum dose of 0.7 mg/L.
(b) One sample location in 2018 had a detection above the MCL. The plant was shut down upon notification of results and treatment media was changed out. No MCL violation occurred.
(c) MCL is based on Gross Alpha minus Uranium.
(d) The State of California has made lead sampling in schools mandatory with a compliance window through 2019.
ND = Not Detected
CaCO3 = Calcium Carbonate
This table includes data only on constituents that were detected.

Source Water Assessment

Golden State Water Company conducted source water assessment in 2003 and in 2014 for the groundwater wells serving the customers of its Norwalk system.

The groundwater sources are considered most vulnerable to the following activities not associated with detected contaminants: active and historic gas stations, chemical/petroleum processing/storage, dry cleaners, known contaminant plumes, and metal plating/finishing/fabricating.

A copy of the assessment may be viewed at:

State Board Los Angeles District Office

500 N. Central Ave., Suite 500
Glendale, CA 91203
Golden State Water Company
Santa Fe Springs Office
12035 Burke St., Suite 1
Santa Fe Springs, CA 90670

You may request a summary of the assessment be sent to you by contacting:
State Board Los Angeles District Office at 1.818.551.2004
For more details, contact Lisa Miller, Water Quality Engineer, at 1.800.999.4033.

In December 2002, The Metropolitan Water District of Southern California (MWD) completed a source water assessment of its Colorado River and State Water Project supplies.

Colorado River supplies are considered to be most vulnerable to the following: increasing urbanization in the watershed, recreation, urban/stormwater runoff, and wastewater.

State Water Project supplies are considered to be most vulnerable to the following: agriculture, recreation, urban/ stormwater runoff, wastewater, and wildlife.

A copy of the assessment can be obtained by contacting MWD by phone at

Laboratory Analyses

Through the years, we have taken thousands of water samples to determine the presence of any radioactive, biological, inorganic, volatile organic, or synthetic organic contaminants in your drinking water. The table we provide shows only detected contaminants in the water.

Even though all the substances listed here are under the Maximum Contaminant Level (MCL), we feel it is important that you know exactly what was detected and how much of these substances were present in your water. Compliance (unless otherwise noted) is based on the average level of concentration below the MCL. The state allows us to monitor for some contaminants less than once per year because the concentrations do not change frequently. Some of our data, while representative, is more than a year old.

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. Golden State Water Company 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 two 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 about lead in drinking water, testing methods and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline at 1.800.426.4791 or at http://www.epa.gov/safewater/lead.

1,4-Dioxane — Notification levels are health-based advisory levels and are not enforceable standards. According to State Board regulations, there is no treatment action needed to be taken to remove 1,4-Dioxane at present. 1,4-Dioxane was found above the Notification Level in a few water sources that supply water to you. Your local governing bodies were notified.

Aluminum — The secondary MCL for aluminum is set for aesthetic reasons and there is no health concern associated with the aluminum levels in this water system.

Chloramination — The water purchased by GSWC from Metropolitan Water District of Southern California (MWD) contains chloramine. Chloramine is added to the water for public health protection. Chloraminated water is safe for people and animals to drink, and for all other general uses. Three special user groups, including kidney dialysis patients, aquarium owners, and businesses or industries that use water in their treatment process, must remove chloramine from the water prior to use.

Hospitals or dialysis centers should be aware of chloramine in the water and should install proper chloramine removal equipment, such as dual carbon adsorption units. Aquarium owners can use readily available products to remove or neutralize chloramine. Businesses and industries that use water in any manufacturing process or for food or beverage preparation should contact their water treatment equipment supplier regarding specific equipment needs.

Fluoridation — Fluoride has been added to the water that GSWC purchases from Metropolitan Water District of Southern California (MWD). Customers should see no difference in the taste, color or odor of their water as a result of fluoridation. Fluoridation does not change the way you normally use water for fish, pets or cooking. Parents and guardians of children who receive fluoride supplements should consult the child’s doctor or dentist. For information regarding fluoridation of your water, please visit the Department of Drinking Water’s fluoridation website at https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/Fluoridation.html.

Nitrate — Nitrate in drinking water at levels above 10 mg/L is a health risk for infants of less than six months of age. Such nitrate levels in drinking water can interfere with the capacity of the infant’s blood to carry oxygen, resulting in a serious illness; symptoms include shortness of breath and blueness of the skin. Nitrate levels above 10 mg/L may also affect the ability of the blood to carry oxygen in other individuals, such as pregnant women and those with certain specific enzyme deficiencies. If you are caring for an infant, or you are pregnant, you should ask for advice from your health care provider.

Odor — The secondary MCL for odor is set for aesthetic reasons and there is no health concern associated with the odor levels in this water system.

Turbidity — Turbidity is a measure of the cloudiness of the water. It is monitored because it is a good indicator of the effectiveness of surface water filtration.

Unregulated Contaminant Monitoring — Monitoring for unregulated contaminants helps the USEPA and the State Board to determine where certain contaminants occur and whether the contaminants need to be regulated.

School Lead Testing — Water quality and protecting public health are top priorities for Golden State Water Company, and we are proud to have partnered with schools throughout our service areas over the last few years to test the drinking water at their facilities for the presence of lead.

California state law (AB 746), established in 2018, requires that all public K-12 schools built before January 1, 2010, have their drinking water tested for lead before the deadline of July 1, 2019. With that deadline approaching, we are pleased to report that the vast majority of schools we serve have already completed testing.

Golden State Water has been working collaboratively with schools to test the water at drinking fountains, cafeterias, food preparation areas and other locations on campus.

To learn more about the school lead testing program and to see if your school has been tested, please visit www.gswater.com/schools.

high quality water supply

Golden State Water’s top priority is to protect the quality of your water supply. In every one of our water systems, a team of highly-trained employees monitors water quality on an on-going basis to ensure that our customers are receiving high-quality water.

Cross Connection Control Program

Golden State Water Company’s Cross Connection Control Program provides a level of certainty that the water in the company’s distribution system is protected from possible backflow of contaminated water from commercial or industrial customers’ premises. For additional information, visit http://www.gswater.com/protecting-our-drinking-water/.

Hydrant Flushing

Hydrant flushing is an essential maintenance procedure that all water providers must perform periodically to ensure the delivery of water that meets state and federal drinking water standards.

Flushing is a necessary part of maintaining the water system and the quality of the water within it. Golden State Water Company has modified procedures to minimize the amount of water released during flushing activities. Water used for flushing represents less than 1 percent of the total water usage in each of our water systems.

For more information about hydrant flushing, visit http://www.gswater.com/flushing-info/.

Connect with us to learn more!

Visit www.gswater.com to:

  • Access the latest Water Quality Report for your area
  • Get the latest updates and news regarding the drought and state/local restrictions
  • Learn more about water-use efficiency, including programs and rebates in your area
  • Understand your water bill and learn about payment options
  • Obtain information about programs for low-income customers (CARW)
  • Sign up to receive email updates about your water service

For additional information, please contact our 24-hour Customer Service Center at
1.800.999.4033 or email us at customerservice@gswater.com.

Risk to Tap and Bottled Water

Drinking water, including bottled water, may reasonably be expected to contain 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 USEPA’s Safe Drinking Water Hotline at 1.800.426.4791.

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

In order to ensure that tap water is safe to drink, the U.S. Environmental Protection Agency (U.S. EPA) and the State Water Resources Control Board (State Board) prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. The U.S. Food and Drug Administration regulations and California law also establish limits for contaminants in bottled water that provide the same protection for public health.

Contaminants in Drinking Water Sources May Include:

  • Microbial contaminants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations and wildlife
  • Inorganic contaminants, such as salts and metals, which can be naturally occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, and farming
  • Pesticides and herbicides that may come from a variety of sources such as agriculture, urban stormwater runoff and residential uses
  • Organic chemical contaminants, including synthetic and volatile organic chemicals, which are byproducts of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff and septic systems
  • Radioactive contaminants that can be naturally occurring or be the result of oil and gas production and mining activities

For People with Sensitive Immune Systems

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised people, such as those individuals with cancer undergoing chemotherapy, those who have undergone organ transplants, those with HIV/AIDS or other immune system disorders, some elderly populations, and infants, can be particularly at risk from infections. These people should seek advice from their health care providers.

The USEPA and Centers for Disease Control issue guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants. To obtain a copy of these guidelines, please call the USEPA’s Safe Drinking Water Hotline at 1.800.426.4791.

About the Company

Golden State Water Company, a subsidiary of American States Water Company (AWR), provides water service to approximately one million Californians located in over 80 communities throughout 10 counties in Northern, Coastal and Southern California. The Company also distributes electricity to more than 24,000 customers in the Big Bear recreational area of California. AWR’s contracted services subsidiary, American States Utility Services, Inc., provides operations, maintenance and construction management services for water and wastewater systems located on military bases throughout the country.

Printed Report

Link to PDF of the printed version of this report: Water-Quality-2019-Norwalk.pdf

To request a paper copy be sent: call 1.800.999.4033 or email waterquality@gswater.com.