Tap Water Quality Report
Tap water quality in ENCINITAS, California
Tap water in ENCINITAS, California receives a grade of D (63/100) 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.
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 concernArsenic detected at 2.8 ppb, 700x above the EWG health guideline of 0.004 ppb.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic 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 concernHaloacetic acids (HAA5) detected at 36.2 ppb, 362x above the EWG health guideline of 0.1 ppb.
EPA compliance record
Official U.S. EPA records for OLIVENHAIN MWD (system ID CA3710029) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for ENCINITAS
Filters matched to the specific contaminants in ENCINITAS's water supply.
Reverse osmosis certified for arsenic (NSF/ANSI 58)
$429-$599Reverse osmosis certified under NSF/ANSI 58 for arsenic is the most reliable home option.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
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.