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2018 Water Quality Data

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2018 Water Quality Data

Water at various locations in the distribution system is tested by certified City staff and a private, state-certified laboratory using the latest testing procedures and equipment. During 2018, numerous tests were conducted on samples taken from the distribution system. In addition to these tests, Valley Water and SFPUC perform their own water quality analyses of the source and treated water.

Test results from the distribution system and source water analyses are shown in the table at right. Some of the data, though representative, are more than one year old. SWRCB allows monitoring for some constituents less than once per year since their concentrations do not change frequently.

Lab analysis was also performed for many constituents other than those listed in the tables; only those constituents detected in the tap water are shown. For a complete list of all the constituents analyzed or any questions about this report, please contact a Water Quality Engineer at 408-277-3671.

Primary Drinking Water Standards - Public Health-Related Standards

Parameter Unit MCL
(MRDL) [AL]		 PHG
(MCLG) [MRDLG]
Evergreen***
(Valley Water Treated)
Evergreen
(Groundwater) 
 Edenvale**
(Groundwater)
Coyote Valley
(Groundwater)
 North San José/Alviso
(SFPUC Treated Water)		 North San José/Alviso
(Groundwater)		 Typical Source
Inorganic Chemicals
 Average Range Average
  Range  
 Average Range Average Range Average Range Average Range  
Aluminum ppm 1 0.6 ND ND - 0.08  0.12b
  ND - 0.5
 0.2b ND - 0.6 NDc ND ND ND NDb ND 1
Arsenic
 ppb
 10
 0.004
 ND ND NDb ND - 2.1 NDb ND NDc ND ND ND ND ND 6, 12
Barium ppm 1 2 ND ND 0.2b 0.2 - 0.2 0.14b 0.13 - 0.15 NDc ND ND ND 0.2b 0.2 - 0.2 1
Fluoride ppm 2 1 0.8 0.6 - 0.9 0.2b 0.2 - 0.2 0.2b 0.2 - 0.3 0.15c  0.15 - 0.15 0.7 0.6 - 1.0 0.1b ND - 0.1 1, 2
Nitrate (as N) ppm 10 10 ND ND - 0.7 2.2 2.1 - 2.3 3.4 2.3 - 4.4 0.6 0.5 - 0.7 ND ND 1.9 0.6 - 3.3 1, 3
Selenium ppb 50 30 ND ND NDb ND NDb ND NDc ND ND ND NDb ND - 6 6
Organic Chemicals             
Total Trihalomethanese ppb 80 NS 45 27 - 53 NA NA NA NA NA NA 45 29 - 51 NA NA 4
Total Haloacetic Acidse ppb 60 NS 13 2 - 20 NA NA NA NA NA NA 43 24 - 53 NA NA 4
Total Organic Carbon ppm TT NS 2.3 1.6 - 3.2 NA NA NA NA NA NA 2.2 1.2 - 2.9 NA NA 15
Bromate
 ppb 10 0.1 2 ND - 4 NA NA NA NA NA NA ND ND NA NA 4
Disinfection            
Chloramine (as chlorine)a ppm (4) [4] 2.5 0.01 - 3.7 NA NA NA NA - 2.9** NA NA - 2.5* 2.8 1.5 - 3.5 NA NA 5
Microbiological            
Giardia Lamblia cyst/L TT (0) ND ND - 0.1 NA NA NA NA NA NA 0.03 ND - 0.24 NA NA 6
  Highest
%		 Range Highest 
% 		 Range
 Highest
%		 Range Highest
%		 Range Highest # Range Highest # Range  
Total Coliforma % pos
per month		 5 (0) 2.9 0 - 2.9 2.9 0 - 2.9 2.9 0 - 2.9 2.9 0 - 2.9 NA NA NA NA 6
# pos
per month		 1 (0) NA NA NA NA NA NA NA NA 0 0 0 0 6
Clarity            
Turbidity
(unfiltered sources)		 NTU 5 NS NA NA NA NA NA NA NA Highest Level
= 1.8
 NA NA 7
Turbidity
(filtered sources)		 NTU 1 NS Highest Level
= 0.19f		 NA NA NA NA NA NA Highest Level
= 1f
 NA NA 7
Lead and Copper 90th Percentile (# Samples Exceeding AL)
Leada ppb [15] 0.2 ND (0 of 51)
 ND (0 of 30) 8
Coppera ppb [1300] 300 220 (0 of 51)
 50 (0 of 30) 8

Secondary Drinking Water Standards — Aesthetic Standards

 Parameter Unit SMCL Evergreen***
(Valley Water 
Treated Water)
Evergreen
(Groundwater) 
 Edenvale**
(Groundwater)		 Coyote Valley
(Groundwater)		 North San José/Alviso
(SFPUC Treated Water)		 North San José
(Groundwater)		 Typical Source
Average Range Average  Range 
 Average Range Average Range Average Range Average Range  
Chloride ppm 500 75 36 - 80 53b 51 - 56 53b 46 - 65 43c 40 - 46 8.9 ND - 17 38b 29 - 46 9, 10
Color CU 15 ND ND 6b ND - 12 5b ND - 10 5c ND - 9 ND ND - 7 5b ND - 10 11
Iron ppm 0.3 ND ND NDb ND NDd ND - 0.13 NDd ND ND ND 0.14 0.1 - 0.2 1
Manganese ppm  0.05 ND ND - 0.04 NDb ND NDd ND - 0.04 NDc ND - 0.02 ND ND 0.02b 0.02 - 0.03 1
Odor TON 3 1 1 - 1 NDb ND NDd ND NDc ND ND ND NDb ND 11
Specific Conductance μS/cm 1600 483 280 - 533 783b 760 - 810 603b 590 - 620 515c 510 - 520 154 29 - 221 665b 570 - 760 10, 14
Sulfate ppm 500 50 26 - 80 72b 67 - 79 51b 49 - 53 38c 37-39 16 0.9 - 29 67b 46 - 87 9, 12
Total Dissolved Solids ppm 1000 284 192 - 292 520b 500 - 560 397b 390 - 400 335c 320 - 350 82 ND - 144 465b 360 - 570 9
Turbidity NTU 5 0.04 0.02 - 0.19 1.3b ND - 4.6 1.1b 0.2 - 1.9 0.6c 0.4 - 0.8 0.1 ND - 0.3 0.31b 0.24 - 0.37 7

Other Water Quality Parameters

Parameter Unit MCL

Evergreen***
(Valley Water 
Treated Water)

 Evergreen
(Groundwater)
 Edenvale**
(Groundwater)		 Coyote Valley
(Groundwater)		 North San José/Alviso
(SFPUC Treated Water)		 North San José
(Groundwater)
Average Range  Average
  Range  Average Range Average Range Average Range Average Range
Boron ppb NS 139 ND - 197 NA NA NA NA NA NA 104 ND - 104 NA NA
Calcium ppm NS 18 11 - 25 63b 57 - 71 44b 39 - 55 42c 41 - 43 11 3 - 18 80b 61 - 98
Hardness
(as CaCO3)g		 ppm NS 91 51 - 126 388b 375 - 401 288b 256 - 304 241c 235 - 247 47 15 - 68 307b 226 - 387
Magnesium ppm NS 11 6 - 16 57b 53 - 63 43b 38 - 51 33c 31 - 35 4 ND - 6 26b 18 - 34
pH - NS 7.8 7.5 - 8 7.2b 7.2 - 7.3 7.5b 7.3 - 7.6 7.4c 7.4 - 7.5 9.4 8.6 - 9.8 7.4b 6.9 - 7.9
Potassium ppm NS 3.1 1.5 - 3.7 1.4b 1.2 - 1.8 0.6b ND - 1.7 1c 1 - 1 0.6 0.2 - 1.0 1.5b 1.3 - 1.7
Silica ppm NS 13 10 - 14 NA NA NA NA NA NA 5 3 - 7 NA NA
Sodium ppm NS 53 31 - 64 41b 35 - 48 33b 28 - 40 20c 18 - 22 14 2 - 20 38b 33 - 42
Total Alkalinity (as CaCO3)  ppm NS 69 42 - 101 338b 320 - 360 233b 200 - 260 180c 180 - 180 51 ND - 132 260b 220 - 300

UCMR4a

Parameter Unit MCL

Evergreen***
(Valley Water 
Treated Water)

 Evergreen
(Groundwater)
 Edenvale**
(Groundwater)		 Coyote Valley
(Groundwater)		 North San José/Alviso
(SFPUC Treated Water)		 North San José
(Groundwater)
Average Range  Average
  Range  Average Range Average Range Average Range Average Range
HAA6Br ppb NS 1.2 ND - 9.5 NA NA NA NA NA NA 0.1 ND - 1.2 NA NA
HAA9 ppb NS 0.9 ND - 9.5 NA NA NA NA NA NA 3.3 ND - 31 NA NA
Manganese ppb NS 1.2 ND - 4.1 ND ND ND ND ND ND 4.2 2.7 - 6.2 33 24 - 56

 

* Temporary chlorination was performed during April 2018 and October 2018 for maintenance purposes. No chlorine was present in the service area during the remainder of the year.

** Valley Water treated surface water was delivered to the Edenvale distribution system during April, May and November 2018. Refer to the Evergreen treated water data column in this table for details on the quality of that water supply.

 *** SFPUC treated water was delivered to the Evergreen System between January and March 2018 via the SFPUC-SCVWD Intertie connection. Refer to the North San José/Alviso treated water data column in this table for details on the quality of that water supply.

Notes:

  1. Distribution system data in 2018
  2. Well data in 2017
  3. Combined well data from 2016 and 2017
  4. Combined well data from 2017 and 2018
  5. Distribution system data in 2018. Running averages are calculated from data for previous quarters that are not shown in this table.
  6. Filtered water turbidity required to be < 0.3 NTU in 95 percent of samples. All filtered water sources met this standard.
  7. To convert hardness from ppm to grains per gallon, divide by 17.1.

Typical Sources in Drinking Water:

  1. Erosion of natural deposits
  2. Water additive that promotes strong teeth
  3. Runoff/leaching from fertilizers
  4. By-product of drinking water disinfection
  5. Added for disinfection
  6. Naturally present in the environment
  7. Soil runoff
  8. Internal corrosion of household plumbing systems
  9. Runoff/leaching of natural deposits
  10. Seawater influence
  1. Naturally occurring organic material
  2. Industrial waste
  3. Industrial discharges
  4. Substances forming ions in water
  5. Various natural and human-made sources
  6. Naturally occurring
  7. Human/animal fecal waste
  8. Discharge from steel and pulp mills, chrome plating
  9. Discharge from metal factories

Definitions:

AL (Regulatory Action Level) The concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.
MCL (Maximum Contaminant Level) 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 technically feasible.
Secondary MCLs are set to protect the odor, taste, and appearance of drinking water.
MCLG (Maximum Contaminant Level Goal) The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are set by the USEPA.
MRDL (Maximum Residual Disinfectant Level) 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.
MRDLG (Maximum Residual Disinfectant Level Goal) 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.
NL (Notification Level) Health-based advisory levels established by the SWRCB for chemicals in drinking water that lack maximum contaminant levels.
PDWS (Primary Drinking Water Standard)  MCLs and MRDLs for contaminants that affect health along with their monitoring, reporting, and water treatment requirements.
PHG (Public Health Goal) 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.
Source Water Raw water that has not been treated to meet drinking water standards.
Treated Water Water that has been treated to meet USEPA and SWRCB drinking water standards.
Treatment Technique  A required process intended to reduce the level of a contaminant in drinking water.

Abbreviations:

 <  less than
 AL  Action Level
 CU  Color Unit
 NA  Not Applicable
 ND  Not Detected
 NS  No Standard
 NTU  Nephelometric Turbidity Units
 pCi/L  pico Curies per liter
 ppb  parts-per-billion (equals 1 microgram per liter (µg/L))
 ppm  parts-per-million (equals 1 milligram per liter (mg/L))
 TON  Threshold Odor Number
 TT  Treatment Technique
 µS/cm  microSiemens per centimeter
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