San Carlos 2020 Water Quality Report

Welcome

We encourage you to review this annual water quality report, also called your Consumer Confidence Report, as it details any constituents detected in your water supply in 2020 and shows how your water compares to federal and state standards.

If you have any questions, please Contact Us. We are here to assist you.

Your Water System

District: Bayshore
System: San Carlos
System ID: #4110007

Cal Water has provided high-quality water utility services in the San Carlos area since 1931. Water for our customers is purchased from the San Francisco Public Utilities Commission (SFPUC). The San Carlos system has 112 miles of main, 18 storage tanks, and 24 booster pumps.

Our company-wide water quality assurance program includes vigilant monitoring throughout our systems and testing at our state-of-the-art laboratory. Additionally, we proactively maintain and upgrade our facilities to ensure a reliable, high-quality supply.

If you have any questions, suggestions, or concerns, please contact our local Customer Center, either by phone at (650) 558-7800 or through the Contact Us page.

Protecting Our Watersheds

The SFPUC conducts watershed sanitary surveys for the Hetch Hetchy source annually and local water sources every five years. The last local sanitary survey was done in 2016. The SFPUC conducted a special watershed sanitary survey for the Upcountry Non-Hetch Hetchy Source (UNHHS) in 2015 as part of its drought response plan efforts. These surveys evaluated the sanitary condition, water quality, potential contamination sources, and results of watershed management activities, and were completed with support from partner agencies including the National Park Service and U.S. Forest Service.

These surveys identified wildlife, stock, and human activities as potential contamination sources. You may contact the San Francisco District office of the State Water Resources Control Board's (SWRCB) Division of Drinking Water (DDW) at (510) 620-3474 to review these activities.

We encourage customers to join us in our efforts to prevent water pollution and protect our most precious natural resource.

The Water Quality Lab

Water professionals collect samples from throughout the water system for testing at our state-of-the-art water quality laboratory, which is certified each year through the stringent Environmental Laboratory Accreditation Program (ELAP). Scientists, chemists, and microbiologists test the water for 326 constituents with equipment so sensitive it can detect levels as low as one part per trillion. In order to maintain the ELAP certification, all of our scientists must pass blind-study proficiency tests for every water quality test performed. Water quality test results are entered into our Laboratory Information Management System (LIMS), a sophisticated software program that enables us to react quickly to changes in water quality and analyze water quality trends in order to plan effectively for future needs.

Possible Contaminants

All 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 United States Environmental Protection Agency (EPA) Safe Drinking Water Hotline at (800) 426-4791.

The sources of drinking water (both tap and bottled) include rivers, lakes, streams, ponds, reservoirs, 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, radioactive material, and can pick up substances resulting from the presence of animals or human activity.

Contaminants that may be present in source water 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, or farming.
• Pesticides and herbicides, which 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, agricultural application, and septic systems.
• Radioactive contaminants, which can be naturally occurring or the result of oil and gas production and mining activities.

In order to ensure that tap water is safe to drink, the EPA and DDW prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. FDA regulations establish limits for contaminants in bottled water, which must provide the same protection for public health.

Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised people, such as those with cancer undergoing chemotherapy, those who have undergone organ transplants, and those with HIV/AIDS or other immune system disorders; some elderly people; and infants can be particularly at risk from infections. These people should seek advice from their health care providers about drinking water. EPA and Centers for Disease Control and Prevention (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.

About Lead

As the issue of lead in water continues to be top of mind for many Americans, Cal Water wants to assure you about the quality of your water. We are compliant with health and safety codes mandating use of lead-free materials in water system replacements, repairs, and new installations. We have no known lead service lines in our systems. We test and treat (if necessary) water sources to ensure that the water delivered to customer meters meets all water quality standards and is not corrosive toward plumbing materials.

The water we deliver to your home meets lead standards. However, 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 (for example, lead solder used to join copper plumbing, and brass and other lead-containing fixtures).

Cal Water is responsible for providing high-quality drinking water to our customers' meters, 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 by a certified lab. More information about lead in drinking water can be found on the Safe Drinking Water Hotline or at www.epa.gov/safewater/lead.

Testing for Lead in Schools

The State of California required that all public schools built before 2010 test for lead in their drinking water by July 1, 2019. We are committed to supporting our school districts' efforts to protect students and ensure that the drinking water at their school sites are below lead limits. We worked with all school districts in our service area that serve kindergarten through 12th grade to develop sampling plans, test samples, and conduct follow-up monitoring, if needed, for corrective actions.

For more information, please see our Testing for Lead in Schools web page. For specific information regarding local school data, see the state web portal.

Lead and Copper Rule

The lead and copper rule requires us to test water inside a representative number of homes that have plumbing most likely to contain lead and/or lead solder to determine the presence of lead and copper or any action level exceedance (AL). An action level is the concentration of a contaminant which, when exceeded, triggers corrective actions before it becomes a health concern. If action levels are exceeded, either at a customer's home or system-wide, we work with the customer to investigate the issue and/or implement corrosion control treatment to reduce lead levels.

Lead Service Line Inventory (LSLI)

Protecting our customers' health and safety is our highest priority. As part of this commitment, we have been working to identify and replace any old customer water service lines and fittings that may contain lead. California Senate Bill (SB) 1398 required all water utilities in California to develop an inventory of all distribution service line materials, and submit a list of known service lines to the state by 2018. A list of unknown service lines that may contain lead, along with a plan for replacement, was due to the state by July 1, 2020. Known lines are replaced as soon as possible.

More information regarding LSLI and specific data for each water system can be found on the state web site.

Key Definitions

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

In Compliance: Does not exceed any applicable MCL, SMCL, or action level, as determined by DDW. For some compounds, compliance is determined by averaging the results for one source over a one-year period.

Regulatory Action Level (AL): The concentration of a contaminant which, if exceeded, triggers treatment or other required action by the water provider.

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 EPA.

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 are set by the EPA and do not reflect the benefits of the use of disinfectants to control microbial contaminants.

Non-Detect (ND): The constituent was not detected.

Notification Level (NL) and Response Level (RL): Health-based advisory levels for unregulated contaminants in drinking water. They are used by DDW to provide guidance to drinking water systems.

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

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's Office of Environmental Health Hazard Assessment without regard to cost or available detection and treatment technologies.

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

Table Introduction

Cal Water tests your water for more than 140 regulated contaminants and dozens of unregulated contaminants. The Water Quality Table lists only those contaminants that were detected.

In the table, water quality test results are divided into several major sections (as needed): "Primary Drinking Water Standards," "Secondary Drinking Water Standards," "State-Regulated Contaminants with Notification Levels," and "Unregulated Compounds." Primary standards protect public health by limiting the levels of certain constituents in drinking water. Secondary standards are set for substances that don't impact health but could affect the water's taste, odor, or appearance. Some unregulated substances (hardness and sodium, for example) are included for your information. 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, are more than one year old.

A list of codes found in the "Source" column and their definitions can be found at the bottom of this page.

Water Quality Table

Primary Drinking Water Standards
Microbiological	Year Tested	Unit	MCL	PHG (MCLG)	In Compliance	Distribution System-Wide		Source
						Highest Monthly
Total coliform	2020	Positive samples	5%	(0)	Yes	4.69%		EN
Fecal coliform and E. coli	2020	Positive samples	11	(0)	Yes	0		FE
	Year Tested	Unit	MCL	PHG (MCLG)	In Compliance	SFPUC Water2		Source
						Range	Average
Giardia lamblia	2020	cyst/L	TT	(0)	Yes	0.0-0.05	0.01	EN
Inorganic	Year Tested	Unit	MCL	PHG (MCLG)	In Compliance	SFPUC Water		Source
						Range	Average
Fluoride	2020	ppm	2.0	1	Yes	ND-0.70	0.30	ER, FL
Lead and Copper	Year Tested	Unit	AL	PHG (MCLG)	In Compliance	Distribution System-Wide		Source
						90th Percentile	Samples > AL
Copper	2018	ppm	1.3	0.3	Yes	ND	0 of 31	IC, ER, WD
Lead	2018	ppb	15	0.2	Yes	ND	0 of 31	IC, ER, IM
Schools that requested lead sampling in 2020: 1
Disinfection Byproducts	Year Tested	Unit	MCL	PHG (MCLG)	In Compliance	Distribution System-Wide		Source
						Range	Highest Annual Average
Haloacetic acids	2020	ppb	60	n/a	Yes	9.1-31	24	DI
Total trihalomethanes	2020	ppb	80	n/a	Yes	14-40	30	DI
Disinfectants	Year Tested	Unit	MRDL	MRDLG	In Compliance	Distribution System-Wide		Source
						Range	Average
Chloramine	2020	ppm	4	4	Yes	0.66-3.3	2.6	DS
Surface Water—Turbidity3	Year Tested	Unit	MCL	PHG (MCLG)	In Compliance	SFPUC Water		Source
						Highest Level	Lowest Monthly Percent
Turbidity—Sunol Valley Water Treatment Plant4	2020	NTU	TT	n/a	Yes	0.40	99.8%	SO
Turbidity—Harry Tracy Water Treatment Plant	2020	NTU	TT	n/a	Yes	0.10	100%	SO
Surface Water—TOC	Year Tested	Unit	MCL	PHG (MCLG)	In Compliance	Range	Average	Source
Total organic carbon (TOC)5	2020	ppm	TT	n/a	Yes	1.7-3.4	2.9	VA
Secondary Drinking Water Standards
Inorganic	Year Tested	Unit	SMCL	PHG (MCLG)	In Compliance	SFPUC Water		Source
						Range	Average
Total dissolved solids	2020	ppm	1000	n/a	Yes	ND-137	72	RU
Specific conductance	2020	µS/cm	1600	n/a	Yes	30-260	160	SW, IN
Chloride	2020	ppm	500	n/a	Yes	ND-15	8.7	RU, SW
Sulfate	2020	ppm	500	n/a	Yes	1.0-34	17	RU, IW
State Regulated Contaminants with Notification Levels
Contaminants	Year Tested	Unit	NL	PHG (MCLG)	In Compliance	SFPUC Water		Source
						Range	Average
Chlorate	2020	ppb	800	n/a	Yes	67-1200	262	UR
Unregulated Contaminant Monitoring Rule (UCMR)
Contaminants	Year Tested	Unit	MCL	PHG (MCLG)	In Compliance	Distribution System-Wide		Source
						Range	Average
HAA5 (DBAA, DCAA, MBAA, MCAA, and TCAA)	2020	ppb	n/a	n/a	n/a	8.1-24	16	UR
HAA6Br (BCAA, BDCAA, DBAA, CDBAA, MBAA, and TBAA)	2020	ppb	n/a	n/a	n/a	ND-2.6	ND	UR
HAA9 (BCAA, BDCAA, CDBAA, DBAA, DCAA, MBAA, MCAA, TBAA, and TCAA)	2020	ppb	n/a	n/a	n/a	10-24	17	UR
Unregulated Compounds
Constituent	Year Tested	Unit	MCL	PHG (MCLG)	In Compliance	SFPUC Water		Source
						Range	Average
Alkalinity (total)	2020	ppm	n/a	n/a	Yes	6.7-138	55	UR
Calcium	2020	ppm	n/a	n/a	Yes	2.9-22	12	UR
Magnesium	2020	ppm	n/a	n/a	Yes	0.20-6.8	4.0	UR
Strontium	2020	ppb	n/a	n/a	Yes	14-242	110	UR
pH	2020	Units	n/a	n/a	Yes	8.6-9.8	9.3	PH
Potassium	2020	ppm	n/a	n/a	Yes	0.30-1.3	0.80	UR
Hardness (total)	2020	ppm	n/a	n/a	Yes	8.0-79	45	UR
Sodium	2020	ppm	n/a	n/a	Yes	2.4-22	14	UR

1 This means one total coliform-positive routine sample and one repeat sample, with one of these also being E. coli-positive.

2 SFPUC supply data reported is from 2020. SFPUC water delivered to our system during 2020 may have been from Valley Water via the SFPUC-Valley Water intertie.

3 SFPUC Water data shown in the table are based on Hetch Hetchy water and effluents from both the Sunol Valley Water Treatment Plant and Harry Tracy Water Treatment Plant.

4 For surface water systems, the treatment technique dictates that the turbidity level of the filtered water be less than or equal to 0.3 NTU in 95% of the measurements taken each month and not exceed 1 NTU at any time. Turbidity is a measurement of the cloudiness of water. We monitor it because it is a good indicator of the effectiveness of our filtration system.

5 TOC has no health effects; however, TOC provides a medium for the formation of disinfection byproducts. These byproducts include trihalomethanes and haloacetic acids. The treatment technique dictates that a removal ratio of 1 or higher must be achieved. Drinking water containing these byproducts in excess of the MCL may lead to adverse health effects such as liver, kidney, or nervous system problems, and may lead to an increased risk of cancer. Concerns regarding disinfection byproducts are based upon exposure over many years.

Substance Sources

Thank You

A full-color, printable version of this report in PDF format is also available.

If you have any questions about your water quality table, please Contact Us.