Tap Water Quality Report
Tap water quality in LAGUNA HILLS, California
Tap water in LAGUNA HILLS, California receives a grade of C (76/100) from TapWaterSafety.org. It's served by MOULTON NIGUEL 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 LAGUNA HILLS's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving LAGUNA HILLS.
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 39.0 ppb, 260x above the EWG health guideline of 0.15 ppb.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 13.6 ppb, 227x above the EWG health guideline of 0.06 ppb.
EPA compliance record
Official U.S. EPA records for MOULTON NIGUEL WATER DISTRICT (system ID CA3010073) 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 LAGUNA HILLS
Filters matched to the specific contaminants in LAGUNA HILLS'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 LAGUNA HILLS'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 |
39.0 ppb | 0.15 | 80.0 | 100 | — | — | — | 260× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
13.6 ppb | 0.06 | — | — | — | — | — | 227× over |
| Bromodichloromethane Disinfection byproduct |
11.6 ppb | 0.06 | — | — | — | — | — | 194× over |
| Dibromochloromethane Disinfection byproduct |
11.1 ppb | 0.1 | — | — | — | — | — | 111× over |
| Dibromoacetic acid Disinfection byproduct |
2.64 ppb | 0.03 | — | — | — | — | — | 88× over |
| Trichloroacetic acid Disinfection byproduct |
4.99 ppb | 0.1 | — | — | — | — | — | 50× over |
| Dichloroacetic acid Disinfection byproduct |
7.47 ppb | 0.2 | — | — | — | — | — | 37× over |
| Chloroform Disinfection byproduct |
13.4 ppb | 0.4 | — | — | — | — | — | 33× over |
| Bromoform Disinfection byproduct |
3.02 ppb | 0.5 | — | — | — | — | — | 6.0× over |
| Chromium (hexavalent) Heavy metal |
0.0749 ppb | 0.02 | — | — | — | — | — | 3.7× over |
| Chlorate Disinfection byproduct |
116.1 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
3.18 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
4.41 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
4.06 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Strontium Radiological |
0.864 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Lithium Other |
33.8 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 MOULTON NIGUEL WATER DISTRICT.