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EWG's Tap Water Database — 2019 UPDATE

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Montara Water and Sanitary District

EWG's drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group by the California State Water Resources Control Board, as well as information from the U.S. EPA Enforcement and Compliance History database (ECHO). For the latest quarter assessed by the U.S. EPA (January 2019 - March 2019), tap water provided by this water utility was in compliance with federal health-based drinking water standards.

Utility Details

  • Montara, California
  • Serves: 4,374
  • Data available: 2012—2017
  • Source: Surface water

Contaminants Detected

13

EXCEED
EWG HEALTH
GUIDELINES

28 Total Contaminants

  • Legal does not necessarily equal safe. Getting a passing grade from the federal government does not mean the water meets the latest health guidelines.
  • Legal limits for contaminants in tap water have not been updated in almost 20 years.
  • The best way to ensure clean tap water is to keep pollution out of source water in the first place.

Legal ≠ Safe

EWG Health Guidelines fill the gap in outdated government standards.

The federal government’s legal limits are not health-protective. The EPA has not set a new tap water standard in almost 20 years, and some standards are more than 40 years old.

Contaminants Detected

1,2,3-Trichloropropane

Potential Effect: cancer2.2x EWG'S HEALTH GUIDELINE
THIS UTILITY0.00155 ppb
EWG HEALTH GUIDELINE0.0007 ppb
NO LEGAL LIMIT
DETAILS
X

1,2,3-Trichloropropane

more about
this contaminant

1,2,3-Trichloropropane is a potent carcinogen that contaminates drinking water in agricultural regions where it was historically used as soil fumigant. Click here to read more about carcinogenic VOCs.

1,2,3-Trichloropropane was found at 2.2 times above EWG's Health Guideline.

EWG Health Guideline

0.0007 ppb or less

This Utility

0.00155 ppb

National Average

0.000454 ppb

State Average

0.000866 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.0007 ppb for 1,2,3-trichloropropane was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

Pollution Sources

industry icon

Industry

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Arsenic

Potential Effect: cancer75x EWG'S HEALTH GUIDELINE
THIS UTILITY0.300 ppb
EWG HEALTH GUIDELINE0.004 ppb
LEGAL LIMIT10 ppb
DETAILS
X

Arsenic is a potent carcinogen and common contaminant in drinking water. Arsenic causes thousands of cases of cancer each year in the U.S. Click here to read more about arsenic.

Arsenic was found at 75 times above EWG's Health Guideline.

EWG Health Guideline

0.004 ppb or less

This Utility

0.3 ppb

Legal Limit

10 ppb

National Average

0.682 ppb

State Average

1.16 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.004 ppb for arsenic was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

Pollution Sources

agriculture icon

Agriculture

industry icon

Industry

naturally occuring icon

Naturally Occurring

Filtering Options

reverse osmosis icon

Reverse Osmosis

ion exchange icon

Ion Exchange

Bromodichloromethane

Potential Effect: cancer5.7x EWG'S HEALTH GUIDELINE
THIS UTILITY0.340 ppb
EWG HEALTH GUIDELINE0.06 ppb
NO LEGAL LIMIT
DETAILS
X

Bromodichloromethane

more about
this contaminant

Bromodichloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Bromodichloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Bromodichloromethane was found at 5.7 times above EWG's Health Guideline.

EWG Health Guideline

0.06 ppb or less

This Utility

0.34 ppb

National Average

5.8 ppb

State Average

4.96 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.06 ppb for bromodichloromethane was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Bromoform

Potential Effect: cancer2.1x EWG'S HEALTH GUIDELINE
THIS UTILITY1.06 ppb
EWG HEALTH GUIDELINE0.5 ppb
NO LEGAL LIMIT
DETAILS
X

Bromoform, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Bromoform and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Bromoform was found at 2.1 times above EWG's Health Guideline.

EWG Health Guideline

0.5 ppb or less

This Utility

1.06 ppb

National Average

1.41 ppb

State Average

3.24 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.5 ppb for bromoform was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Dibromoacetic acid

Potential Effect: 83x EWG'S HEALTH GUIDELINE
THIS UTILITY3.31 ppb
EWG HEALTH GUIDELINE0.04 ppb
NO LEGAL LIMIT
DETAILS
X

Dibromoacetic acid

more about
this contaminant

Dibromoacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Dibromoacetic acid was found at 83 times above EWG's Health Guideline.

EWG Health Guideline

0.04 ppb or less

This Utility

3.31 ppb

National Average

1.17 ppb

State Average

2.21 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.04 ppb for dibromoacetic acid was defined in a peer-reviewed scientific study by EWG and represents a on-in-a-million lifetime cancer risk level. This health guideline protects against cancer.

Pollution Sources

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Dibromochloromethane

Potential Effect: cancer7.5x EWG'S HEALTH GUIDELINE
THIS UTILITY0.747 ppb
EWG HEALTH GUIDELINE0.1 ppb
NO LEGAL LIMIT
DETAILS
X

Dibromochloromethane

more about
this contaminant

Dibromochloromethane, one of the total trihalomethanes (TTHMs), is formed when chlorine or other disinfectants are used to treat drinking water. Dibromochloromethane and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Dibromochloromethane was found at 7.5 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

0.747 ppb

National Average

3.41 ppb

State Average

5.61 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.1 ppb for dibromochloromethane was proposed in 2018 by the California Office of Environmental Health Hazard Assessment as a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Dichloroacetic acid

Potential Effect: cancer3.7x EWG'S HEALTH GUIDELINE
THIS UTILITY0.733 ppb
EWG HEALTH GUIDELINE0.2 ppb
NO LEGAL LIMIT
DETAILS
X

Dichloroacetic acid

more about
this contaminant

Dichloroacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Dichloroacetic acid was found at 3.7 times above EWG's Health Guideline.

EWG Health Guideline

0.2 ppb or less

This Utility

0.733 ppb

National Average

7.82 ppb

State Average

4.51 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.2 ppb for dichloroacetic acid was proposed in 2020 by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk.a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Haloacetic acids (HAA5)

Potential Effect: 52x EWG'S HEALTH GUIDELINE
THIS UTILITY5.18 ppb
EWG HEALTH GUIDELINE0.1 ppb
LEGAL LIMIT60 ppb
DETAILS
X

Haloacetic acids (HAA5)

more about
this contaminant

Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of five haloacetic acids regulated by federal standards includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid.

Haloacetic acids (HAA5) was found at 52 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

5.18 ppb

Legal Limit

60 ppb

National Average

17.2 ppb

State Average

13.8 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.1 ppb for the group of five haloacetic acids, or HAA5, was defined in a peer-reviewed scientific study by EWG and represents a on-in-a-million lifetime cancer risk level. This health guideline protects against cancer.

Pollution Sources

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Manganese

Potential Effect: harm to the brain and nervous system4.4x EWG'S HEALTH GUIDELINE
THIS UTILITY441.8 ppb
EWG HEALTH GUIDELINE100 ppb
NO LEGAL LIMIT
DETAILS
X

Manganese is a naturally occurring element that is common in food and drinking water. Excessive manganese exposures may impair children's attention, memory and intellectual capacity. Click here to read more about manganese.

Manganese was found at 4.4 times above EWG's Health Guideline.

EWG Health Guideline

100 ppb or less

This Utility

441.8 ppb

National Average

12.5 ppb

State Average

8.01 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 100 ppb for manganese was defined by the state of Minnesota as a health risk limit, the concentration of a contaminant that can be consumed with little or no risk to health. This health guideline protects against harm to the brain and nervous system.

Pollution Sources

industry icon

Industry

naturally occuring icon

Naturally Occurring

Filtering Options

ion exchange icon

Ion Exchange

Nitrate

Potential Effect: cancer20x EWG'S HEALTH GUIDELINE
THIS UTILITY2.74 ppm
EWG HEALTH GUIDELINE0.14 ppm
LEGAL LIMIT10 ppm
DETAILS
X

Nitrate, a fertilizer chemical, frequently contaminates drinking water due to agricultural and urban runoff, and discharges from municipal wastewater treatment plants and septic tanks. Excessive nitrate in water can cause oxygen deprivation in infants and increase the risk of cancer. Click here to read more about nitrate.

Nitrate was found at 20 times above EWG's Health Guideline.

EWG Health Guideline

0.14 ppm or less

This Utility

2.74 ppm

Legal Limit

10 ppm

National Average

0.937 ppm

State Average

1.84 ppm
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppm = parts per million

Health Risks

The EWG Health Guideline of 0.14 ppm for nitrate was defined by EWG . This health guideline protects against cancer and harm to fetal growth and development.

Pollution Sources

agriculture icon

Agriculture

urban area icon

Runoff & Sprawl

naturally occuring icon

Naturally Occurring

Filtering Options

reverse osmosis icon

Reverse Osmosis

ion exchange icon

Ion Exchange

Nitrate and nitrite

Potential Effect: cancer18x EWG'S HEALTH GUIDELINE
THIS UTILITY2.47 ppm
EWG HEALTH GUIDELINE0.14 ppm
LEGAL LIMIT10 ppm
DETAILS
X

Nitrate and nitrite

more about
this contaminant

Nitrate and nitrite enter water from fertilizer runoff, septic tanks and urban runoff. These contaminants can cause oxygen deprivation for infants and increase the risk of cancer. Nitrite is significantly more toxic than nitrate. Click here to read more about nitrate.

Nitrate and nitrite was found at 18 times above EWG's Health Guideline.

EWG Health Guideline

0.14 ppm or less

This Utility

2.47 ppm

Legal Limit

10 ppm

National Average

0.891 ppm

State Average

1.73 ppm
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppm = parts per million

Health Risks

The health guideline of 0.14 parts per million, or ppm, for nitrate and nitrite is based on the equivalent health guideline for nitrate, as defined in a peer-reviewed scientific study by EWG. This guideline represents a one-in-one-million annual cancer risk level.

Pollution Sources

agriculture icon

Agriculture

urban area icon

Runoff & Sprawl

naturally occuring icon

Naturally Occurring

Filtering Options

reverse osmosis icon

Reverse Osmosis

ion exchange icon

Ion Exchange

Total trihalomethanes (TTHMs)

Potential Effect: cancer56x EWG'S HEALTH GUIDELINE
THIS UTILITY8.33 ppb
EWG HEALTH GUIDELINE0.15 ppb
LEGAL LIMIT80 ppb
DETAILS
X

Total trihalomethanes (TTHMs)

more about
this contaminant

Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform.

Total trihalomethanes (TTHMs) was found at 56 times above EWG's Health Guideline.

EWG Health Guideline

0.15 ppb or less

This Utility

8.33 ppb

Legal Limit

80 ppb

National Average

30.1 ppb

State Average

31.1 ppb
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The health guideline of 0.15 parts per billion, or ppb, for the group of four trihalomethanes, or THM4/TTHM, was defined in a peer-reviewed scientific study by EWG and represents a one-in-one-million lifetime cancer risk level.

Pollution Sources

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Trichloroacetic acid

Potential Effect: cancer11x EWG'S HEALTH GUIDELINE
THIS UTILITY1.13 ppb
EWG HEALTH GUIDELINE0.1 ppb
NO LEGAL LIMIT
DETAILS
X

Trichloroacetic acid

more about
this contaminant

Trichloroacetic acid, one of the group of five haloacetic acids regulated by federal standards, is formed when chlorine or other disinfectants are used to treat drinking water. Haloacetic acids and other disinfection byproducts increase the risk of cancer and may cause problems during pregnancy. Click here to read more about disinfection byproducts.

Trichloroacetic acid was found at 11 times above EWG's Health Guideline.

EWG Health Guideline

0.1 ppb or less

This Utility

1.13 ppb

National Average

6.42 ppb

State Average

3.5 ppb
NO LEGAL LIMIT
The state and national averages were calculated using the averages of the contaminant measurements for each utility in 2015-2017.
ppb = parts per billion

Health Risks

The EWG Health Guideline of 0.1 ppb for trichloroacetic acid was proposed in 2020 by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk.a one-in-a-million lifetime risk of cancer. Values greater than one-in-a-million cancer risk level can result in increased cancer cases above one in a million people.

Pollution Sources

water treatment icon

Treatment Byproducts

Filtering Options

carbon filter icon

Activated Carbon

reverse osmosis icon

Reverse Osmosis

Includes chemicals detected in 2015-2017 for which annual utility averages exceeded an EWG-selected health guideline established by a federal or state public health authority.


Other Contaminants Tested


Contaminants detected between 2012 and 2014 and were not part of EPA's UCMR-3 testing program or radiologicals:

Carbon tetrachloride, Toluene

 

Chemicals tested for but not detected from 2012 to 2017:

1,1,1,2-Tetrachloroethane, 1,1,1-Trichloroethane, 1,1,2,2-Tetrachloroethane, 1,1,2-Trichloroethane, 1,1-Dichloroethane, 1,1-Dichloroethylene, 1,1-Dichloropropene, 1,2,3-Trichlorobenzene, 1,2,4-Trichlorobenzene, 1,2,4-Trimethylbenzene, 1,2-Dibromo-3-chloropropane (DBCP), 1,2-Dichloroethane, 1,3,5-Trimethylbenzene, 1,3-Butadiene, 1,3-Dichloropropane, 1,3-Dichloropropene, 1,4-Dioxane, 2,2-Dichloropropane, 2,3,7,8-TCDD (Dioxin), 2,4,5-T, 2,4,5-TP (Silvex), 2,4-D, 2,4-Dinitrotoluene, 2-Chloroethylvinyl ether, 3-Hydroxycarbofuran, Acetone, Alachlor (Lasso), Aldicarb, Aldicarb sulfone, Aldicarb sulfoxide, Aldrin, Antimony, Asbestos, Atrazine, Barium, Baygon (Propoxur), Bentazon (Basagran), Benzene, Benzo[a]pyrene, Beryllium, bis(2-chloroethyl) ether, Bromacil, Bromobenzene, Bromochloromethane, Bromomethane, Butachlor, Cadmium, Caffeine, Carbaryl, Carbofuran, Chlordane, Chlorodifluoromethane, Chloroethane, Chloromethane, Chlorothalonil (Bravo), Chlorotoluene, cis-1,3-Dichloropropene, Cyanide, Dalapon, Di(2-ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, Diazinon (Spectracide), Dibromomethane, Dicamba, Dichlorodifluoromethane, Dichloromethane (methylene chloride), Dieldrin, Dimethoate, Dinoseb, Diquat, Endothall, Endrin, Ethyl tert-butyl ether, Ethylbenzene, Ethylene dibromide, Germanium, Glyphosate, Heptachlor, Heptachlor epoxide, Hexachlorobenzene (HCB), Hexachlorobutadiene, Hexachlorocyclopentadiene, Isopropyl ether, Isopropylbenzene, Lindane, m-Dichlorobenzene, Mercury (inorganic), Methiocarb, Methomyl, Methoxychlor, Methyl ethyl ketone, Methyl isobutyl ketone, Metolachlor, Metribuzin, Molinate, Monobromoacetic acid, Monochloroacetic acid, Monochlorobenzene (chlorobenzene), MTBE, n-Butylbenzene, n-Propylbenzene, Naphthalene, Nitrite, o-Chlorotoluene, o-Dichlorobenzene, Oxamyl (Vydate), p-Chlorotoluene, p-Dichlorobenzene, p-Isopropyltoluene, Pentachlorophenol, Perchlorate, Perfluorobutane sulfonate (PFBS), Perfluoroheptanoic acid (PFHPA), Perfluorohexane sulfonate (PFHXS), Perfluorononanoic acid (PFNA), Perfluorooctane sulfonate (PFOS), Perfluorooctanoic acid (PFOA), Picloram, Polychlorinated biphenyls (PCBs), Propachlor, sec-Butylbenzene, Silver, Simazine, Styrene, Tellurium, tert-Amyl methyl ether, tert-Butyl alcohol, tert-Butylbenzene, Tetrachloroethylene (perchloroethylene), Thallium, Thiobencarb, Toxaphene, trans-1,3-Dichloropropene, Trichlorofluoromethane, Trichlorotrifluoroethane, Trifluralin, Vinyl chloride, Xylenes (total)

Montara Water and Sanitary District compliance with legally mandated federal standards:

  • From April 2016 to March 2019, Montara Water and Sanitary District complied with health-based drinking water standards.

Information in this section on Montara Water and Sanitary District comes from the U.S. EPA Enforcement and Compliance History Online database (ECHO).

LEARN MORE ABOUT THIS UTILITY

Water Filters That Can Reduce Contaminant Levels

ContaminantActivated Carbonactivated carbonReverse Osmosisreverse osmosisIon Exchangeion exchange
CONTAMINANTS ABOVE
HEALTH GUIDELINES
1,2,3-Trichloropropane
Arsenic
Bromodichloromethane
Bromoform
Dibromoacetic acid
Dibromochloromethane
Dichloroacetic acid
Haloacetic acids (HAA5)
Manganese
Nitrate
Nitrate & nitrite
Total trihalomethanes (TTHMs)
Trichloroacetic acid
OTHER CONTAMINANTS
DETECTED
1,2-Dichloropropane
Aluminum
Chlorate
Chloroform
Chromium (hexavalent)
Chromium (total)
cis-1,2-Dichloroethylene
Cobalt
Fluoride
Molybdenum
Selenium
Strontium
trans-1,2-Dichloroethylene
Trichloroethylene
Vanadium

Take Action

Contact Your Local Official

One of the best ways to push for cleaner water is to hold accountable the elected officials who have a say in water quality – from city hall and the state legislature to Congress all the way to the Oval Office – by asking questions and demanding answers.

LEARN MORE

Filter Out Contaminants

Check out our recommendations for filters to protect your water against the detected contaminants.

EWG’S WATER FILTER GUIDE