Physical & aggregate
Specific Conductance in U.S. tap water
88 public water systems across 14 U.S. states report Specific Conductance in their annual Consumer Confidence Report. 20 sit at or above the federal limit.
What it is
A measure of how well water conducts electricity, which tracks dissolved mineral content.
Why it's regulated
Not federally regulated for health; used as a proxy for total dissolved solids.
At or above the federal limit (20)
| Water system | Measured | vs. limit |
|---|---|---|
| Ventura, CA 2023 annual report | 1791 | 1791.0× the limit |
| Torrance, CA 2024 annual report | 1000–1400 | 1400.0× the limit |
| Irvine, CA 2023 annual report | 1001 | 1001.0× the limit |
| Costa Mesa, CA 2024 annual report | 996 | 996.0× the limit |
| Fullerton, CA 2024 annual report | 996 | 996.0× the limit |
| Pomona, CA 2024 annual report | 912–996 | 996.0× the limit |
| Santa Ana, CA 2024 annual report | 979 | 979.0× the limit |
| Oxnard, CA 2024 annual report | 918 | 918.0× the limit |
| Huntington Beach, CA 2025 annual report | 873 | 873.0× the limit |
| Inglewood, CA 2023 annual report | 855 | 855.0× the limit |
| El Cajon, CA 2024 annual report | 800 | 800.0× the limit |
| El Monte, CA 2024 annual report | 460–800 | 800.0× the limit |
| Burbank, CA 2024 annual report | 498–740 | 740.0× the limit |
| Rialto, CA 2024 annual report | 520 | 520.0× the limit |
| Overland Park, KS 2023 annual report | 510 | 510.0× the limit |
| Ontario, CA 2024 annual report | 508 | 508.0× the limit |
| Vallejo, CA 2024 annual report | 427 | 427.0× the limit |
| West Covina, CA 2024 annual report | 420 | 420.0× the limit |
| Fontana, CA 2024 annual report | 404.5 | 404.5× the limit |
| Hayward, CA 2024 annual report | 174 | 174.0× the limit |
Approaching the limit (1)
| Water system | Measured | vs. limit |
|---|---|---|
| Glendale, CA 2024 annual report | 1300 uS/cm | 0.8× the limit |
Within the federal limit (50)
| Water system | Measured |
|---|---|
| City of Hemet, CA 2024 annual report | 1120 uS/cm |
| City of Menifee, CA 2024 annual report | 1120 uS/cm |
| City of Murrieta, CA 2024 annual report | 1120 uS/cm |
| City of Perris, CA 2024 annual report | 1120 uS/cm |
| City of San Jacinto, CA 2024 annual report | 1120 uS/cm |
| City of Temecula, CA 2024 annual report | 1120 uS/cm |
| East Valley Service Area, CA 2024 annual report | 1120 uS/cm |
| Mills Service Area, CA 2024 annual report | 1120 uS/cm |
| Moreno Valley, CA 2024 annual report | 1120 uS/cm |
| Skinner Service Area, CA 2024 annual report | 1120 uS/cm |
| Tracy, CA 2024 annual report | 1039 uS/cm |
| San Diego, CA 2023 annual report | 980 |
| Escondido, CA 2024 annual report | 814 uS/cm |
| Salinas, CA 2024 annual report | 809 |
| Thousand Oaks, CA 2024 annual report | 773–790 % |
| Simi Valley, CA 2024 annual report | 782 % |
| Pasadena, CA 2023 annual report | 733 |
| Sunnyvale, CA 2024 annual report | 662 |
| Vacaville, CA 2024 annual report | 589 |
| Santa Rosa, CA 2024 annual report | 450–490 |
| Fairfield, CA 2024 annual report | 385 |
| Chico, CA 2024 annual report | 296 |
| Victorville, CA 2024 annual report | 273 |
| Hesperia, CA 2024 annual report | 262 |
| Visalia, CA 2024 annual report | 226 |
| Alameda, CA 2024 annual report | 127 |
| Albany, CA 2024 annual report | 127 |
| Berkeley, CA 2024 annual report | 127 |
| Castro Valley, CA 2024 annual report | 127 |
| Crockett, CA 2024 annual report | 127 |
| El Cerrito, CA 2024 annual report | 127 |
| El Sobrante, CA 2024 annual report | 127 |
| Emeryville, CA 2024 annual report | 127 |
| Hayward, CA 2024 annual report | 127 |
| Hercules, CA 2024 annual report | 127 |
| Kensington, CA 2024 annual report | 127 |
| Lafayette, CA 2024 annual report | 127 |
| Moraga, CA 2024 annual report | 127 |
| Oakland, CA 2024 annual report | 127 |
| Orinda, CA 2024 annual report | 127 |
| Piedmont, CA 2024 annual report | 127 |
| Pinole, CA 2024 annual report | 127 |
| Richmond, CA 2024 annual report | 127 |
| Rodeo, CA 2024 annual report | 127 |
| San Leandro, CA 2024 annual report | 127 |
| San Lorenzo, CA 2024 annual report | 127 |
| San Pablo, CA 2024 annual report | 127 |
| Daly City, CA 2024 annual report | 193 |
| San Francisco SFPUC, CA 2023 annual report | 193 |
| San Mateo, CA 2024 annual report | 193 |
Frequently asked
+What is Specific Conductance?
A measure of how well water conducts electricity, which tracks dissolved mineral content. Not federally regulated for health; used as a proxy for total dissolved solids.
+What is the federal limit for Specific Conductance in drinking water?
The federal MCL for Specific Conductance is 900 . The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.
+How many U.S. water systems have Specific Conductance over the federal limit?
20 of the 88 public water systems on The Water Map report Specific Conductance at or above its federal limit, spanning 14 U.S. states. The full list is on this page.
+How can I check if Specific Conductance is in my city's tap water?
Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including Specific Conductance.