The Power of Information

National Drinking Water Database


Hidden Valley Lake Csd - Upper Lake, CA


Serves 6,757 people - Test data available: 2004-2009

This drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group (EWG) by the California Department of Public Health. It is part of EWG's national database that includes 47,667 drinking water utilities and 20 million test results. Water utilities nationwide detected more than 300 pollutants between 2004 and 2009. More than half of these chemicals are unregulated, legal in any amount. Despite this widespread contamination, the federal government invests few resources to protecting rivers, reservoirs, and groundwater from pollution in the first place. The information below summarizes test results for this utility and lists potential health concerns.

 
This Drinking Water System
National Average
Exceed Health GuidelinesTests showing chemicals at concentrations above health guidelines established by federal and state health agencies. These guidelines are typically set at a levels that pose no significant health risk.
6 chemicals
4
Health Standard ExceedencesChemicals detected at concentrations above the legal limit, the Maximum Contaminant Level (MCLs) established by the U.S. EPA. Most MCLs are based on annual averages, so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.
0 chemicals
0.5
Pollutants FoundThe total number of contaminants detected since 2004, according to data provided by the state water agency.
14 chemicals
8
Tests ConductedThe total number of number of water quality tests conducted by water utilities and recorded in data provided by the state water agency.
309 tests
420

Contaminants Exceeding Health Guidelines

ContaminantAverage/
Maximum
Result
Health Limit
Exceeded
Legal Limit
Exceeded

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
Alpha particle activityAlpha particles are a form of radiation released from mining waste pollutants and natural sources.0.49 pCi/L
1.13 pCi/L
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 pCi/L
No
15 pCi/L
Radium-228Radium-228 is a radioactive element usually found around uranium deposits.0.07 pCi/L
0.25 pCi/L
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 pCi/L
No
5 pCi/L
BromoformBromoform is a disinfection byproduct from the trihalomethane (THM) family, and is formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.1.03 ppb
1.6 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
80 ppb
DibromochloromethaneDibromochloromethane is a disinfection byproduct from the trihalomethane (THM) family, and is formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.0.85 ppb
1.6 ppb
Yes
0.4 ppb
No
80 ppb
Arsenic (total)Arsenic contaminates drinking water due to mining runoff, erosion of natural deposits, emissions from glass and electronics processing and the use of arsenical compounds as wood preservatives and pesticides.0.68 ppb
2.7 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
10 ppb
BromodichloromethaneBromodichloromethane is a disinfection byproduct from the trihalomethane (THM) family, and is formed when chlorine, chloramines or other disinfectants react with organic and inorganic matter in water.0.21 ppb
0.62 ppb
Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb
No
80 ppb
NOTE: Each dot in the above graph represents one month.
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

Other Detected Contaminants

ContaminantAverage/
Maximum
Result
Health Limit
Exceeded
Legal Limit
Exceeded

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
NitrateNitrate enters drinking water sources from fertilizer runoff, leaching septic tanks, and erosion of natural deposits; it is also emitted by chemical, petrochemical and metal-finishing industries.2.13 ppm
2.94 ppm
No
10 ppm
No
10 ppm
Chromium (total)Chromium is a metal that pollutes drinking water due to discharge from steel and pulp mills and erosion of natural deposits.22.72 ppb
32 ppb
No
100 ppb
No
100 ppb
Chromium (hexavalent)Chromium is a metal that pollutes drinking water due to discharge from steel and pulp mills and erosion of natural deposits.23.5 ppb
28 ppb
NoNo
100 ppb
Barium (total)Barium is a mineral that enters drinking water through drilling and mining waste runoff, discharges from chemical industries and erosion of natural deposits.52.5 ppb
110 ppb
No
700 ppb
No
2000 ppb
Total trihalomethanes (TTHMs)Total trihalomethanes constitute the sum of four disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, and bromoform.2.17 ppb
3.8 ppb
No
9.8 ppb
No
80 ppb
Combined Uranium (pCi/L)Uranium is a radioactive element commonly found in most rocks; processed ore is used for power generation and weapons manufacture.0.06 pCi/L
0.08 pCi/L
NoNo
15 pCi/L
Nitrate & nitriteNitrate and nitrite enter water from fertilizer runoff, leaching from septic tanks, and erosion of natural deposits.<0.01 ppm
<0.01 ppm
No
10 ppm
No
10 ppm
TritiumTritium is a pollutant from commercial nuclear reactors, research reactors and government weapons production plants.195 pCi/L
195 pCi/L
NoLegal at any levelThis is the Federal Limit. State Limits may be lower.
NOTE: Each dot in the above graph represents one month.
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

Contaminants Not Detected - 117 chemicals

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, 1,2,3-Trichloropropane, 1,2,4-Trichlorobenzene, 1,2,4-Trimethylbenzene, 1,2-Dichloroethane, 1,2-Dichloropropane, 1,3,5-Trimethylbenzene, 1,3-Dichloropropane, 1,3-Dichloropropene, 2,2-Dichloropropane, 2,4,5-t, 2,4,5-TP (Silvex), 2,4-d, 2,4-db, 2-Chloroethylvinyl ether, 3-Hydroxycarbofuran, Alachlor (Lasso), Aldicarb, Aldicarb sulfone, Aldicarb sulfoxide, Aldrin, Aluminum, Antimony (total), Asbestos, Atrazine, Baygon (Propoxur), Bentazon (Basagran), Benzene, Beryllium (total), Bromobenzene, Bromochloromethane, Bromomethane, Cadmium (total), Carbaryl, Carbofuran, Carbon tetrachloride, Chlordane, Chloroethane, Chloroform, Chloromethane, cis-1,2-Dichloroethylene, Copper, Dalapon, Dibromoacetic acid, Dibromomethane, Dicamba, Dichloroacetic acid, Dichlorodifluoromethane, Dichloromethane (methylene chloride), Dieldrin, Dinoseb, Diquat, Endothall, Endrin, Ethyl-t-butyl ether (ETBE), Ethylbenzene, Ethylene dibromide (EDB), Heptachlor, Heptachlor epoxide, Hexachlorobenzene (HCB), Hexachlorobutadiene, Hexachlorocyclopentadiene, Isopropylbenzene, Lead (total), Lindane, m- & p- Xylene, m-Dichlorobenzene, Manganese, Mercury (total inorganic), Methiocarb, Methomyl, Methoxychlor, Monobromoacetic acid, Monochloroacetic acid, Monochlorobenzene (Chlorobenzene), Mtbe, n-Butylbenzene, n-Propylbenzene, Nitrite, o-Chlorotoluene, o-Dichlorobenzene, o-Xylene, Oxamyl (Vydate), p-Chlorotoluene, p-Dichlorobenzene, p-Isopropyltoluene, Pentachlorophenol, Perchlorate, Picloram, sec-Butylbenzene, Selenium (total), Silver (total), Simazine, Strontium-90, Styrene, Tert-Amyl-Methyl Ether, Tert-Butyl Alcohol, tert-Butylbenzene, Tetrachloroethylene, Thallium (total), Toluene, Total haloacetic acids (HAAs), Toxaphene, trans-1,2-Dichloroethylene, Trichloroacetic acid, Trichloroethylene, Trichlorofluoromethane, Trichlorotrifluoroethane, Vinyl chloride, Xylenes (total)

Pollution Summary

14Total Contaminants Detected (2004 - 2009)

Arsenic (total), Barium (total), Chromium (total), Nitrate & nitrite, Nitrate, Chromium (hexavalent), Bromoform, Bromodichloromethane, Dibromochloromethane, Total trihalomethanes (TTHMs), Radium-228, Tritium, Alpha particle activity, Combined Uranium (pCi/L)

3Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Arsenic (total), Nitrate & nitrite, Nitrate

3Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Arsenic (total), Nitrate & nitrite, Nitrate

10Industrial Pollutants

Arsenic (total), Barium (total), Chromium (total), Nitrate & nitrite, Nitrate, Chromium (hexavalent), Radium-228, Tritium, Alpha particle activity, Combined Uranium (pCi/L)

4Water Treatment and Distribution Byproducts
(pipes and fixtures, treatment chemicals and byproducts)

Total trihalomethanes (TTHMs), Bromodichloromethane, Dibromochloromethane, Bromoform

9Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate, Nitrate & nitrite, Barium (total), Arsenic (total), Radium-228, Alpha particle activity, Combined Uranium (pCi/L), Chromium (total), Chromium (hexavalent)

1Unregulated Contaminants
EPA has not established a maximum legal limit in tapwater for these contaminants

Tritium

EPA Violation Summary

Violation CategoryNumber of Violations
MCL and Treatment
(click see violations)
1

Information on violations is drawn directly from EPA's national violations database in the Agency's Safe Drinking Water Information System. Analyses by others have raised questions about the quality of the information in EPA's database. For the purposes of this investigation, EWG is not showing below or including in our analyses, those violations for individual water suppliers that occurred on days for which the total number of violations assigned by EPA to that water supplier was greater than 20. This criteria was based on common characteristics of incorrect violations data as identified by water utilities, from a review of EPA's violations data by several hundred utilities prior to the release of EWG's investigation.