Tennant C.S.D.

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: 50 people
Connections: 102
Water source: Groundwater
Based in: Macdoel, CA
County: Siskiyou
Owner: Local government
Hardness: Soft

The ZIP code it serves

96058

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

Nitrate, arsenic, chromium (total) and fluoride: California’s own results, samples taken from Feb. 7, 2020 to April 3, 2026.

Below EPA’s limits1

Nitrate

Comes from the source

Below EPA’s limits

0.39ppm

Highest sample; found in 5 of 7

2026, one sample: 0.37 ppm

The highest sample, in 2025, was 0.39 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its one sample was 0.37 ppm.

What handles it

NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

4 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.

Arsenic
Chromium (total)
Fluoride
Lead

Hardness

Soft, 34 mg/L (2 grains per gallon), at its one sampling point, in 2026.

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.

Softeners compared at 2 grains per gallon, salt included Softener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or rule	Type	Period	Measured	Status
Lead and Copper Rule Revisions	The required inventory of lead service lines was not completed or submitted on time.EPA: LSL Inventory	Oct. 17, 2024	—	Unaddressed
Revised Total Coliform Rule	Coliform results required a check of the system, and the check or its fixes were not done on time.EPA: Treatment Technique, Level 1 Assessment (RTCR)	Sept. 1, 2018	—	Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 2 monitoring or reporting violations not shown.

What this report can’t tell you

Everything else. Nitrate, arsenic, chromium (total) and fluoride results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Tennant C.S.D.’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 Feb. 7, 2020 to April 3, 2026.

Testing your own tap

Tennant C.S.D.’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab California certifies.

The lab California certifies closest to the area Tennant C.S.D. serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.