Del Oro Water Co. - Hat Creek District
What EPA’s and California’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.
- Serves
- 211 people
- Connections
- 64
- Water source
- Surface water
- Based in
- Chico, CA
- County
- Shasta
- Owner
- Private
- Hardness
- Moderately hard
The ZIP code it serves
The short answer
Nothing in EPA’s and California’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. 2 health-based violations since 2016.
What was found
Haloacetic acids (HAA5), total trihalomethanes (TTHM), arsenic, chromium (total), fluoride and nitrate: California’s own results, samples taken from Aug. 24, 2021 to Aug. 26, 2025.
Below EPA’s limits2
Haloacetic acids (HAA5)
Forms or is added in treatment
28.9ppb
Highest yearly average, 2021 to 2025
Averaged by year, the highest was 28.9 ppb, in 2025, below EPA’s legal limit of 60 ppb. That was also the latest year on file.
What handles it
No certification claim covers this compound yet.
Total trihalomethanes (TTHM)
Forms or is added in treatment
36.2ppb
Highest yearly average, 2021 to 2025
Averaged by year, the highest was 36.2 ppb, in 2025, below EPA’s legal limit of 80 ppb. That was also the latest year on file.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
5 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Arsenic
- Chromium (total)
- Fluoride
- Lead
- Nitrate
Hardness
Moderately hard, 63 mg/L (3.7 grains per gallon), at its one sampling point, in 2021.
Hardness is calcium and magnesium. EPA sets no limit for it: it shows up as scale on fixtures and in water heaters, and as soap that won’t lather. USGS calls water above 60 mg/L moderately hard, above 120 hard and above 180 very hard.
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| Interim Enhanced Surface Water Treatment Rule | Too many readings in a month showed cloudiness above the filtration standard.EPA: Monthly Turbidity Exceed (Enhanced SWTR) | May 1, 2016 to May 31, 2016 | — | Resolved |
| Interim Enhanced Surface Water Treatment Rule | Too many readings in a month showed cloudiness above the filtration standard.EPA: Monthly Turbidity Exceed (Enhanced SWTR) | March 1, 2016 to March 31, 2016 | — | Resolved |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 4 monitoring or reporting violations not shown. | ||||
What this report can’t tell you
Everything else. Haloacetic acids (HAA5), total trihalomethanes (TTHM), arsenic, chromium (total), fluoride and nitrate results here are California’s own from 2021 on, with EPA’s national file for 2012 to 2019. Del Oro Water Co. - Hat Creek District’s own annual report, which it must send you every year, has the contaminants this page does not show.
Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.
Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; California’s results run from Aug. 24, 2021 to Aug. 26, 2025.
Testing your own tap
The 2 labs California certifies closest to the area Del Oro Water Co. - Hat Creek District serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Pace Analytical Services, LLC - Redding
Redding, CA · about 49 miles
Certified for bacteria
Fruit Growers Laboratory, Inc.
Chico, CA · about 66 miles
Certified for bacteria
Sources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- California State Water Resources Control Board, Division of Drinking Water, results from Jan. 1, 2020 to July 17, 2026, read Oct. 8, 2026
- Certified labs: California State Water Resources Control Board, ELAP accredited laboratories and their fields of accreditation, read Oct. 17, 2026; distances from the Census 2020 ZIP code tabulation area gazetteer
- Hardness: California State Water Resources Control Board, Division of Drinking Water, results from Oct. 26, 2021 to Oct. 26, 2021, read Oct. 10, 2026
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID CA4500022. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Nothing here is above a health goalIn EPA’s and California’s records for this utility. They don’t cover everything, which is why the next step matters.Every contaminant TapBuff tracks
- Get the utility’s own reportDel Oro Water Co. - Hat Creek District must send you a water quality report every year. It covers contaminants this page does not show.How to read it
- Test your own tap for leadYour service line, solder and fixtures decide the lead at your faucet, not the utility’s average.Lead in your water: what to do
- Decide if you want a filter at allA filter for taste or chlorine is a preference, not a need. The standards say what each kind can do.NSF/ANSI standards, decoded