Drinking water quality · 2023

What's in California Water Service Co. - Dominguez — San Jose, Ca, CA tap water

33 contaminants were measured in the California Water Service Co. - Dominguez — San Jose, Ca, CA water system's 2023 annual report. Each is shown below against its federal limit.

Browse the mapFull source report ↗

Reporting year: 2023
Contaminants measured: 33
Over federal limit: 0
Approaching the limit: 0
Service area: CA
Source: Utility CCR

All within federal limits. Every measured contaminant in this report is below its federal threshold.

Compliance history

Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.

Maximum contaminant level exceededHealth-based
1 violation on record · most recent Oct 1995
resolved

Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗

Disinfection byproducts

Contaminant	Measured	Federal limit	Status
BromateA disinfection byproduct formed when bromide-containing water is treated with ozone.	7.9 ug/LRunning annual avgMills Plant	None set	Within the limit
+By source (5)— Mills Plant, Weymouth Plant, Skinner Plant +2 more Mills PlantPlant avg7.9 ug/Lrange0–19 ug/L190% of limit Weymouth PlantPlant avg2 ug/Lrange0–9.2 ug/L92% of limit Skinner PlantPlant avg1.5 ug/Lrange0–6 ug/L60% of limit Jensen PlantPlant avg3.1 ug/Lrange0–5.4 ug/L54% of limit Diemer PlantPlant avgNot detected ug/Lrange0–1.6 ug/L16% of limit
TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter.	45 ug/LRunning annual avgDistribution System Highest LRAA	None set	Within the limit
+By source (9)— Skinner Plant, Distribution System, Distribution System-Wide +6 more Skinner PlantPlant avg34 ug/Lrange15–48 ug/L60% of limit Distribution SystemZone range12–48 ug/L60% of limit Distribution System-WideZone range0–47 ug/L59% of limit Distribution System Highest LRAAZone avg45 ug/L56% of limit Diemer PlantPlant avg44 ug/Lrange24–30 ug/L55% of limit Mills PlantPlant avg44 ug/Lrange14–29 ug/L55% of limit Distribution System-Wide Highest AnnualZone avg39 ug/L49% of limit Weymouth PlantPlant avg32 ug/Lrange28–37 ug/L46% of limit Jensen PlantPlant avg21 ug/Lrange13–27 ug/L34% of limit
HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter.	19 ug/LRunning annual avgDiemer Plant	None set	Within the limit
+By source (9)— Skinner Plant, Distribution System, Distribution System-Wide +6 more Skinner PlantPlant avg12 ug/Lrange1.2–23 ug/L38% of limit Distribution SystemZone range0–23 ug/L38% of limit Distribution System-WideZone range0–19 ug/L32% of limit Diemer PlantPlant avg19 ug/Lrange0–9.5 ug/L32% of limit Distribution System Highest LRAAZone avg19 ug/L32% of limit Distribution System-Wide Highest AnnualZone avg13 ug/L22% of limit Mills PlantPlant avg13 ug/Lrange0–5.7 ug/L22% of limit Weymouth PlantPlant avg6.2 ug/Lrange0–4.2 ug/L10% of limit Jensen PlantPlant avg5.6 ug/Lrange1.3–5 ug/L9% of limit
ChlorateA byproduct that can form during disinfection, especially when hypochlorite solutions degrade.	80 ug/LAverageSkinner Plant	800 ug/LNL	Detected — no federal limit
+By source (5)— Skinner Plant, Weymouth Plant, Mills Plant +2 more Skinner PlantPlant avg80 ug/Lrange80 ug/L Weymouth PlantPlant avg80 ug/Lrange80 ug/L Mills PlantPlant avg78 ug/Lrange78 ug/L Diemer PlantPlant avg77 ug/Lrange77 ug/L Jensen PlantPlant avg70 ug/Lrange70 ug/L
N-Nitrosodi-n-butylamine	2.5 ug/LAverageDiemer Plant	50 ug/LNL	Detected — no federal limit
+By source (5)— Diemer Plant, Jensen Plant, Mills Plant +2 more Diemer PlantPlant avg2.5 ug/Lrange2.5 ug/L Jensen PlantPlant avgNot detected ug/LrangeNot detected ug/L Mills PlantPlant avgNot detected ug/LrangeNot detected ug/L Skinner PlantPlant avgNot detected ug/LrangeNot detected ug/L Weymouth PlantPlant avgNot detected ug/LrangeNot detected ug/L
NDMA	2.5 ng/LAverageSkinner Plant	10 ng/LNL	Detected — no federal limit
+By source (6)— Distribution System, Skinner Plant, Diemer Plant +3 more Distribution SystemZone avgNot detected ng/Lrange0–3 ng/L Skinner PlantPlant avg2.5 ng/Lrange2.5 ng/L Diemer PlantPlant avgNot detected ng/LrangeNot detected ng/L Jensen PlantPlant avgNot detected ng/LrangeNot detected ng/L Mills PlantPlant avgNot detected ng/LrangeNot detected ng/L Weymouth PlantPlant avgNot detected ng/LrangeNot detected ng/L

Disinfectants

Contaminant	Measured	Federal limit	Status
ChloramineA longer-lasting disinfectant made by combining chlorine with ammonia.	2.5 mg/LRunning annual avgDistribution System Highest LRAA	4 mg/LMCL	Within the limit
+By source (2)— Distribution System, Distribution System Highest LRAA Distribution SystemZone range1.6–3 mg/L75% of limit Distribution System Highest LRAAZone avg2.5 mg/L63% of limit

Other

Contaminant	Measured	Federal limit	Status
Chlorine Total	2 mg/LAverageDistribution System-Wide	4 mg/LMCL	Within the limit

Metals

Contaminant	Measured	Federal limit	Status
CopperA metal that enters water from corroding household plumbing.	0.307 mg/L90th percentileDistribution System-Wide	1.3 mg/LAction level	Within the limit
LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures.	0.0018 mg/L90th percentileAt the tap	0.015 mg/LAction level	Within the limit
BariumA metal from erosion of natural deposits and industrial discharge.	124 ug/LAverageDiemer Plant	None set	Within the limit
+By source (5)— Diemer Plant, Weymouth Plant, Jensen Plant +2 more Diemer PlantPlant avg124 ug/Lrange124 ug/L6% of limit Weymouth PlantPlant avg124 ug/Lrange124 ug/L6% of limit Jensen PlantPlant avgNot detected ug/LrangeNot detected ug/L0% of limit Mills PlantPlant avgNot detected ug/LrangeNot detected ug/L0% of limit Skinner PlantPlant avgNot detected ug/LrangeNot detected ug/L0% of limit
SeleniumA trace element from natural deposits and industrial discharge.	Not detected ug/LAverageGroundwater	None set	Within the limit
AluminumA common element sometimes used as a treatment coagulant.	93 ug/LAverageWeymouth Plant	None set	Detected — no federal limit
+By source (5)— Skinner Plant, Weymouth Plant, Diemer Plant +2 more Skinner PlantPlant avg74 ug/Lrange0–160 ug/L Weymouth PlantPlant avg93 ug/Lrange0–150 ug/L Diemer PlantPlant avgNot detected ug/Lrange0–110 ug/L Mills PlantPlant avgNot detected ug/Lrange0–110 ug/L Jensen PlantPlant avg62 ug/Lrange52–91 ug/L
BoronA naturally occurring element from rock and soil.	170 ug/LAverageJensen Plant	1000 ug/LNL	Detected — no federal limit
+By source (5)— Jensen Plant, Diemer Plant, Weymouth Plant +2 more Jensen PlantPlant avg170 ug/Lrange170 ug/L Diemer PlantPlant avg140 ug/Lrange140 ug/L Weymouth PlantPlant avg140 ug/Lrange140 ug/L Mills PlantPlant avg130 ug/Lrange130 ug/L Skinner PlantPlant avg130 ug/Lrange130 ug/L
CalciumA naturally occurring mineral that contributes to water hardness.	68 mg/LAverageDiemer Plant	None set	Detected — no federal limit
+By source (6)— Groundwater, Diemer Plant, Weymouth Plant +3 more GroundwaterPlant avg37 mg/Lrange17–100 mg/L Diemer PlantPlant avg68 mg/Lrange58–78 mg/L Weymouth PlantPlant avg68 mg/Lrange59–76 mg/L Skinner PlantPlant avg62 mg/Lrange61–62 mg/L Jensen PlantPlant avg38 mg/Lrange38–39 mg/L Mills PlantPlant avg18 mg/Lrange15–22 mg/L
LithiumA naturally occurring element found in some groundwater.	40 ug/LAverageDiemer Plant	None set	Detected — no federal limit
+By source (6)— Diemer Plant, Weymouth Plant, Skinner Plant +3 more Diemer PlantPlant avg40 ug/Lrange32–47 ug/L Weymouth PlantPlant avg40 ug/Lrange32–47 ug/L Skinner PlantPlant avg28 ug/Lrange24–32 ug/L GroundwaterPlant avgNot detected ug/LrangeNot detected ug/L Jensen PlantPlant avgNot detected ug/LrangeNot detected ug/L Mills PlantPlant avgNot detected ug/LrangeNot detected ug/L
MagnesiumA naturally occurring mineral that contributes to water hardness.	26 mg/LAverageDiemer Plant	None set	Detected — no federal limit
+By source (6)— Diemer Plant, Weymouth Plant, Skinner Plant +3 more Diemer PlantPlant avg26 mg/Lrange22–29 mg/L Weymouth PlantPlant avg26 mg/Lrange23–29 mg/L Skinner PlantPlant avg22 mg/Lrange22–23 mg/L GroundwaterPlant avg8.2 mg/Lrange1.6–19 mg/L Jensen PlantPlant avg14 mg/Lrange13–14 mg/L Mills PlantPlant avg9.7 mg/Lrange8.4–11 mg/L
PotassiumA naturally occurring mineral from rock and soil.	5 mg/LAverageWeymouth Plant	None set	Detected — no federal limit
+By source (6)— Groundwater, Diemer Plant, Weymouth Plant +3 more GroundwaterPlant avg2.7 mg/Lrange1.1–5.7 mg/L Diemer PlantPlant avg4.9 mg/Lrange4.4–5.4 mg/L Weymouth PlantPlant avg5 mg/Lrange4.6–5.4 mg/L Skinner PlantPlant avg4.8 mg/Lrange4.6–4.9 mg/L Mills PlantPlant avg2.5 mg/Lrange1.9–3.1 mg/L Jensen PlantPlant avg2.6 mg/Lrange2.6 mg/L
SodiumA naturally occurring salt component.	105 mg/LAverageWeymouth Plant	None set	Detected — no federal limit
+By source (6)— Weymouth Plant, Diemer Plant, Skinner Plant +3 more Weymouth PlantPlant avg105 mg/Lrange93–117 mg/L Diemer PlantPlant avg103 mg/Lrange90–116 mg/L Skinner PlantPlant avg93 mg/Lrange91–95 mg/L GroundwaterPlant avg59 mg/Lrange46–82 mg/L Mills PlantPlant avg44 mg/Lrange35–54 mg/L Jensen PlantPlant avg46 mg/Lrange46 mg/L

Inorganic chemicals

Contaminant	Measured	Federal limit	Status
FluorideA mineral often added to drinking water to help prevent tooth decay.	0.7 mg/LAverageDiemer Plant	4 mg/LMCL	Within the limit
+By source (7)— Mills Plant, Diemer Plant, Jensen Plant +4 more Mills PlantPlant avg0.7 mg/Lrange0.6–0.9 mg/L23% of limit Diemer PlantPlant avg0.7 mg/Lrange0.6–0.8 mg/L20% of limit Jensen PlantPlant avg0.7 mg/Lrange0.6–0.8 mg/L20% of limit Skinner PlantPlant avg0.7 mg/Lrange0.6–0.8 mg/L20% of limit Weymouth PlantPlant avg0.7 mg/Lrange0.3–0.8 mg/L20% of limit Distribution SystemZone avg0.7 mg/Lrange0.3–0.8 mg/L20% of limit GroundwaterPlant avg0.53 mg/Lrange0.16–0.74 mg/L19% of limit
NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits.	0.6 mg/LAverageMills Plant	10 mg/LMCL	Within the limit
+By source (5)— Mills Plant, Jensen Plant, Diemer Plant +2 more Mills PlantPlant avg0.6 mg/Lrange0.6 mg/L6% of limit Jensen PlantPlant avg0.5 mg/Lrange0.5 mg/L5% of limit Diemer PlantPlant avgNot detected mg/LrangeNot detected mg/L0% of limit Skinner PlantPlant avgNot detected mg/LrangeNot detected mg/L0% of limit Weymouth PlantPlant avgNot detected mg/LrangeNot detected mg/L0% of limit

Physical & aggregate

Contaminant	Measured	Federal limit	Status
TurbidityA measure of cloudiness from suspended particles in the water.	0.08 NTUMaximumMills Plant	None set	Within the limit
+By source (5)— Mills Plant, Skinner Plant, Diemer Plant +2 more Mills PlantPlant 8% of limit Skinner PlantPlant 7% of limit Diemer PlantPlant 6% of limit Weymouth PlantPlant 6% of limit Jensen PlantPlant 4% of limit
AlkalinityA measure of the water's capacity to neutralize acids.	154 mg/LAverageGroundwater	None set	Detected — no federal limit
+By source (6)— Groundwater, Weymouth Plant, Diemer Plant +3 more GroundwaterPlant avg154 mg/Lrange130–190 mg/L Weymouth PlantPlant avg118 mg/Lrange109–127 mg/L Diemer PlantPlant avg114 mg/Lrange105–123 mg/L Skinner PlantPlant avg105 mg/Lrange103–107 mg/L Jensen PlantPlant avg98 mg/Lrange94–101 mg/L Mills PlantPlant avg70 mg/Lrange68–71 mg/L
HardnessA measure of dissolved calcium and magnesium minerals.	272 mg/LAverageWeymouth Plant	None set	Detected — no federal limit
+By source (6)— Diemer Plant, Weymouth Plant, Groundwater +3 more Diemer PlantPlant avg270 mg/Lrange235–305 mg/L Weymouth PlantPlant avg272 mg/Lrange241–303 mg/L GroundwaterPlant avg126 mg/Lrange48–300 mg/L Skinner PlantPlant avg242 mg/Lrange242–243 mg/L Jensen PlantPlant avg148 mg/Lrange143–153 mg/L Mills PlantPlant avg84 mg/Lrange68–99 mg/L
pHA measure of how acidic or basic the water is.	8.7AverageMills Plant	None set	Detected — no federal limit
+By source (6)— Groundwater, Mills Plant, Jensen Plant +3 more GroundwaterPlant avg7.9range5.9–9.7 Mills PlantPlant avg8.7range8.7–8.8 Jensen PlantPlant avg8.3range8.2–8.3 Diemer PlantPlant avg8.2range8.2 Weymouth PlantPlant avg8.2range8.2 Skinner PlantPlant avg8.1range8.1
TOCTotal organic carbon — a measure of organic material dissolved in the water.	2.6 mg/LRunning annual avgSkinner Plant	None set	Detected — no federal limit
+By source (5)— Skinner Plant, Weymouth Plant, Diemer Plant +2 more Skinner PlantPlant avg2.6 mg/Lrange2.3–3 mg/L Weymouth PlantPlant avg2.4 mg/Lrange2.1–2.6 mg/L Diemer PlantPlant avg2.4 mg/Lrange2–2.5 mg/L Jensen PlantPlant avg2.4 mg/Lrange2–2.5 mg/L Mills PlantPlant avg2.2 mg/Lrange1.5–2.5 mg/L
Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts.	590 mg/LAverageDiemer Plant	None set	Detected — no federal limit
+By source (5)— Diemer Plant, Weymouth Plant, Skinner Plant +2 more Diemer PlantPlant avg590 mg/Lrange492–682 mg/L Weymouth PlantPlant avg587 mg/Lrange506–680 mg/L Skinner PlantPlant avg559 mg/Lrange493–597 mg/L Jensen PlantPlant avg304 mg/Lrange295–313 mg/L Mills PlantPlant avg222 mg/Lrange169–262 mg/L

Microbial

Contaminant	Measured	Federal limit	Status
Escherichia coli (E. coli)Escherichia coli — bacteria found in the gut of humans and animals.	0MaximumDistribution System-Wide Highest Monthly	None set	None detected
Total ColiformA group of bacteria used as an indicator of overall water-system sanitation.	0.1 %AverageDistribution System	None set	Detected — no federal limit

Radionuclides

Contaminant	Measured	Federal limit	Status
Combined RadiumCombined radium-226 and radium-228 — naturally occurring radioactive elements.	Not detected pCi/LAverageJensen Plant	0.019 pCi/LPublic health goal	Within the limit
+By source (5)— Mills Plant, Diemer Plant, Jensen Plant +2 more Mills PlantPlant avgNot detected pCi/Lrange0–1 pCi/L20% of limit Diemer PlantPlant avgNot detected pCi/LrangeNot detected pCi/L0% of limit Jensen PlantPlant avgNot detected pCi/LrangeNot detected pCi/L0% of limit Skinner PlantPlant avgNot detected pCi/LrangeNot detected pCi/L0% of limit Weymouth PlantPlant avgNot detected pCi/LrangeNot detected pCi/L0% of limit
Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances.	Not detected pCi/LAverageGroundwater	15 pCi/LMCL	Within the limit
+By source (6)— Diemer Plant, Skinner Plant, Groundwater +3 more Diemer PlantPlant avgNot detected pCi/Lrange0–5 pCi/L33% of limit Skinner PlantPlant avgNot detected pCi/Lrange0–4 pCi/L27% of limit GroundwaterPlant avgNot detected pCi/Lrange0–3 pCi/L20% of limit Jensen PlantPlant avgNot detected pCi/LrangeNot detected pCi/L0% of limit Mills PlantPlant avgNot detected pCi/LrangeNot detected pCi/L0% of limit Weymouth PlantPlant avgNot detected pCi/LrangeNot detected pCi/L0% of limit
Gross Beta Particle ActivityGross beta particle activity — a combined measure of beta-emitting radioactive substances.	4 pCi/LAverageDiemer Plant	None set	Detected — no federal limit
+By source (5)— Diemer Plant, Skinner Plant, Weymouth Plant +2 more Diemer PlantPlant avg4 pCi/Lrange0–5 pCi/L Skinner PlantPlant avg4 pCi/Lrange0–5 pCi/L Weymouth PlantPlant avgNot detected pCi/Lrange0–5 pCi/L Jensen PlantPlant avgNot detected pCi/LrangeNot detected pCi/L Mills PlantPlant avgNot detected pCi/LrangeNot detected pCi/L
UraniumA naturally occurring radioactive metal from erosion of natural deposits.	2 pCi/LAverageJensen Plant	20 pCi/LMCL	Detected — no federal limit
+By source (5)— Diemer Plant, Jensen Plant, Skinner Plant +2 more Diemer PlantPlant avg1 pCi/Lrange0–3 pCi/L Jensen PlantPlant avg2 pCi/Lrange2–3 pCi/L Skinner PlantPlant avg2 pCi/Lrange0–3 pCi/L Weymouth PlantPlant avgNot detected pCi/Lrange0–3 pCi/L Mills PlantPlant avgNot detected pCi/LrangeNot detected pCi/L

Source: California Water Service Co. - Dominguez — San Jose, Ca, CA's 2023 Consumer Confidence Report — the annual drinking-water report every U.S. utility is required to publish. The numbers on this page are the utility's own. A water-quality report covers an entire service area, not a single address.