Is MAMMOTH CWD's water safe to drink?
MAMMOTH CWD has a health-based violation on record, but none in the last five years - an older issue, not necessarily a current one. It serves 8,234 people through 3,818 service connections.
MAMMOTH CWD's record against the rest of the country
Out of 12,903 systems in this dataset, MAMMOTH CWD ranks 5,495th by violation burden (57th percentile) - 6 violations total, 3 health-baseds.
How MAMMOTH CWD compares within CA
Among the 803 CA systems in this dataset, the average is 5.8 health-based violations - MAMMOTH CWD's 3 is at or below that. The filter guide explains what a violation like this actually calls for.
Most recent violation on record
The last violation EPA has on record for MAMMOTH CWD is from 2023-01-01 (health-based: 2016-01-08). Last reported to EPA: 06/22/2026.
What kind of problem, specifically
MAMMOTH CWD's flagged contaminants and rule violations, grouped by what they actually mean for a filter choice rather than left as EPA's raw code list:
- Microbial contamination / treatment technique - flagged from: Coliform (TCR); Surface Water Treatment Rule
The most severe category on record is microbial contamination / treatment technique, which points toward a microbial-class filter if you want to address it directly.
What this data is and is not
MAMMOTH CWD's numbers here come from its own required reporting to EPA under the Safe Drinking Water Act, not from an independent test of your glass of water. Between the utility's meter and MAMMOTH CWD's customers' taps is household plumbing, invisible to a system-level record ranked 5,495th of 12,903 by violation count. The guide to what this data misses covers that gap.