Tap Water Quality Report

Tap water quality in ENCINITAS, California

Served by OLIVENHAIN MWD. 86,458 residents.

Average score 59/100
Utilities 1
Population 86,458
Quick answer

Tap water in ENCINITAS, California receives a grade of F (59/100) from TapWaterSafety.org. It's served by OLIVENHAIN MWD. The most significant water quality concerns are: Arsenic significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.

Data sources for this grade: utilities.csv EWG Tap Water Database ⓘ How did we get this rating?

What's in ENCINITAS's tap water

Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving ENCINITAS.

Arsenic significantly above health guideline

Moderate concern

Arsenic detected at 2.8 ppb, 700x above the EWG health guideline of 0.004 ppb.

Haloacetic acids (HAA9) significantly above health guideline

Moderate concern

Haloacetic acids (HAA9) detected at 28.0 ppb, 467x above the EWG health guideline of 0.06 ppb.

Haloacetic acids (HAA5) significantly above health guideline

Moderate concern

Haloacetic acids (HAA5) detected at 36.2 ppb, 362x above the EWG health guideline of 0.1 ppb.

Recommended filters for ENCINITAS

Filters matched to the specific contaminants in ENCINITAS's water supply.

Reverse Osmosis

$249-$750

Arsenic is most effectively removed by reverse osmosis. Some specialized adsorptive filters also work.

AquaTru Countertop Reverse Osmosis
$449-$599 NSF 42, 53, 58, 401, P473
Editorial pick · affiliate link coming soon
Aquasana OptimH2O Reverse Osmosis + Claryum
$429-$549 NSF 42, 53, 58, 401, P473
Editorial pick · affiliate link coming soon
Waterdrop G3P800 Tankless RO
$600-$750 NSF 58, 372
View on retailer →
Waterdrop N1 Countertop RO
$249-$329 NSF 58, 372
View on retailer →

Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.

All contaminants detected in ENCINITAS's tap water

Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →

Contaminant Detected EWG
US health-based
EPA
US legal
EU DWD
Europe
WHO
global
CA PHG
strictest US
Tested
sample year
Status
Arsenic
Heavy metal
2.8 ppb 0.004 10.0 10 10 0.004 700× over
Haloacetic acids (HAA9)
Disinfection byproduct
28.0 ppb 0.06 467× over
Haloacetic acids (HAA5)
Disinfection byproduct
36.2 ppb 0.1 60.0 60 362× over
Total trihalomethanes (TTHMs)
Disinfection byproduct
33.9 ppb 0.15 80.0 100 226× over
Bromodichloromethane
Disinfection byproduct
10.5 ppb 0.06 175× over
Dibromochloromethane
Disinfection byproduct
10.2 ppb 0.1 102× over
Dibromoacetic acid
Disinfection byproduct
1.66 ppb 0.03 55× over
Trichloroacetic acid
Disinfection byproduct
3.43 ppb 0.1 34× over
Chloroform
Disinfection byproduct
10.1 ppb 0.4 25× over
Dichloroacetic acid
Disinfection byproduct
4.54 ppb 0.2 23× over
Bromoform
Disinfection byproduct
3.15 ppb 0.5 6.3× over
Uranium
Radiological
1.34 pCi/L 0.43 20.0 30 30 0.43 3.1× over
Chromium (hexavalent)
Heavy metal
0.0364 ppb 0.02 1.8× over
Chlorate
Disinfection byproduct
174.3 ppb 210.0 Below guideline
Bromochloromethane
Other
0.0347 ppb 0.06 Below guideline
Barium
Heavy metal
110.0 ppb 700.0 2000.0 1300 2000 Below guideline
Molybdenum
Other
3.81 ppb 40.0 Below guideline
Vanadium
Other
1.73 ppb 21.0 Below guideline
Manganese
Heavy metal
0.814 ppb 100.0 50 80 Below guideline
Strontium
Radiological
0.8 ppb 1500.0 Below guideline
Fluoride
Inorganic
0.658 ppm 4.0 1.5 1.5 Below guideline
Lithium
Other
50.2 ppb Below guideline

All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.

Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.

Treatment plant contact info

For service issues, water quality concerns, or to request a Consumer Confidence Report from OLIVENHAIN MWD.

Treatment Plant

FacilityOLIVENHAIN WTP - TREATED

ZIP codes served

ENCINITAS's public water systems serve the following ZIP codes: