Tap Water Quality Report
Tap water quality in RANCHO SANTA MARGARITA, California
Tap water in RANCHO SANTA MARGARITA, California receives a grade of C (75/100) from TapWaterSafety.org. It's served by SANTA MARGARITA WATER DISTRICT. The most significant water quality concerns are: Haloacetic acids (HAA5) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in RANCHO SANTA MARGARITA's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving RANCHO SANTA MARGARITA.
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.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 36.3 ppb, 242x above the EWG health guideline of 0.15 ppb.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 11.7 ppb, 195x above the EWG health guideline of 0.06 ppb.
EPA compliance record
Official U.S. EPA records for SANTA MARGARITA WATER DISTRICT (system ID CA3010101) 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 RANCHO SANTA MARGARITA
Filters matched to the specific contaminants in RANCHO SANTA MARGARITA's water supply.
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 RANCHO SANTA MARGARITA'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 |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA5) Disinfection byproduct |
36.2 ppb | 0.1 | 60.0 | 60 | — | — | — | 362× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
36.3 ppb | 0.15 | 80.0 | 100 | — | — | — | 242× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
11.7 ppb | 0.06 | — | — | — | — | — | 195× over |
| Bromodichloromethane Disinfection byproduct |
9.73 ppb | 0.06 | — | — | — | — | — | 162× over |
| Dibromochloromethane Disinfection byproduct |
11.3 ppb | 0.1 | — | — | — | — | — | 113× over |
| Dibromoacetic acid Disinfection byproduct |
1.61 ppb | 0.03 | — | — | — | — | — | 54× over |
| Bromochloroacetic acid Disinfection byproduct |
1.06 ppb | 0.02 | — | — | — | — | — | 53× over |
| Trichloroacetic acid Disinfection byproduct |
3.24 ppb | 0.1 | — | — | — | — | — | 32× over |
| Chloroform Disinfection byproduct |
11.8 ppb | 0.4 | — | — | — | — | — | 29× over |
| Dichloroacetic acid Disinfection byproduct |
5.11 ppb | 0.2 | — | — | — | — | — | 26× over |
| Bromoform Disinfection byproduct |
3.54 ppb | 0.5 | — | — | — | — | — | 7.1× over |
| Chromium (hexavalent) Heavy metal |
0.126 ppb | 0.02 | — | — | — | — | — | 6.3× over |
| Bromochloromethane Other |
0.13 ppb | 0.06 | — | — | — | — | — | 2.2× over |
| Chlorate Disinfection byproduct |
225.0 ppb | 210.0 | — | — | — | — | — | 1.1× over |
| Vanadium Other |
2.36 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
3.63 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
2.15 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Strontium Radiological |
0.793 ppb | 1500.0 | — | — | — | — | — | 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 SANTA MARGARITA WATER DISTRICT.