Grindstone Rancheria
Grindstone Rancheria (EPA ID 090605004) in ELK Creek, CA supplies surface water (rivers, lakes) to about 150 people: 100 violations since 2016, latest lead result 5 ppb, PFAS not tested.
Health-based violations since 2016: Surface Water Treatment Rule, Revised Total Coliform Rule, Stage 1 Disinfectants and Disinfection Byproducts Rule. 12 are still listed as unresolved in EPA records.
90th-percentile lead in the latest round (Jan 2023). Lead comes mostly from household plumbing and service lines, so individual homes can be higher.
This system was not part of EPA’s 2023–2025 nationwide PFAS testing (UCMR 5 covers systems serving over 3,300 people and a sample of smaller ones).
Service area
EPA service-area boundary (state-supplied or EPA-modeled)System facts
Health-based violations
| Contaminant or rule | Health-based violations since 2016 |
|---|---|
| Surface Water Treatment Rule | 78 |
| Revised Total Coliform Rule | 20 |
| Stage 1 Disinfectants and Disinfection Byproducts Rule | 2 |
A health-based violation means a contaminant exceeded its legal limit (MCL) or a required treatment technique was not met, as reported by the state to EPA’s SDWIS. 12 still listed as unresolved (“unaddressed” or “addressed” but not yet returned to compliance); the latest began Mar 2024.
Lead
90th-percentile lead per sampling round (90% of the homes sampled were at or below this level). Black line: EPA’s 15 ppb action level; under the Lead and Copper Rule Improvements the action level becomes 10 ppb from 2027.
PFAS
This system was not part of EPA’s 2023–2025 nationwide PFAS testing (UCMR 5).
What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.
Questions
Has Grindstone Rancheria had drinking water violations?
Health-based violations since 2016: Surface Water Treatment Rule, Revised Total Coliform Rule, Stage 1 Disinfectants and Disinfection Byproducts Rule. 12 are still listed as unresolved in EPA records.
What is the lead level in Grindstone Rancheria water?
The latest 90th-percentile lead result (Jan 2023) was 5 ppb. EPA’s action level is 15 ppb (10 ppb from 2027).
Does Grindstone Rancheria have PFAS in its water?
This system was not part of EPA’s 2023–2025 nationwide PFAS testing (UCMR 5 covers systems serving over 3,300 people and a sample of smaller ones).