San Lucas County Water 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
- 315 people
- Connections
- 94
- Water source
- Groundwater
- Based in
- San Lucas, CA
- County
- Monterey
- Owner
- Private
- Hardness
- Very hard
The ZIP code it serves
The short answer
1 result is above EPA’s legal limit, 1 more is above the limit’s level with no violation recorded, and 3 more are above the health goal. The worst: Nitrate, above the legal limit. 6 health-based violations since 2016.
What handles itWhat was found
Lead and copper: EPA SDWIS monitoring periods ending 2011 to 2025.
Nitrate, total trihalomethanes (TTHM), uranium, arsenic, haloacetic acids (HAA5), fluoride and chromium (total): California’s own results, samples taken from Jan. 7, 2020 to July 9, 2026, with EPA’s 2012 to 2019 file for earlier years.
Above the legal limit1
Nitrate
Comes from the source
19.9ppm
Highest sample; found in 205 of 333
2026 average: 1.3 ppm
From 2020 to 2021, four samples were above EPA’s legal limit of 10 ppm, the highest 19.9 ppm in 2021. Every one came back under the limit on the next sample at the same point. In 2026, the latest year on file, its 27 samples averaged 1.3 ppm. EPA recorded violations for nitrate at this utility in 2020 and 2021. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 42.9 ppm, in 2014, and EPA recorded violations in 2013, 2014, 2016, 2018 and 2019.
What handles it
- NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
- NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
Above the limit’s level, no violation recorded1
Total trihalomethanes (TTHM)
Forms or is added in treatment
103ppb
Highest yearly average, 2020 to 2026
2026 average: 37 ppb
Averaged by year, the highest was 103 ppb, in 2022, above EPA’s legal limit of 80 ppb. Its highest single sample was 111 ppb. In 2026, the latest year on file, its two samples averaged 37 ppb. EPA judges this limit on running averages at each sampling point, and recorded no violation for total trihalomethanes (TTHM) at this utility since 2020. Results like these with no violation often include water sampled before treatment or blending; the utility’s annual report says what reaches the tap. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 13.7 ppb, in 2017.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
Above the health goal3
Uranium
Comes from the source
12ppb
Highest yearly average, 2020 to 2026
2026 average: 4.5 ppb
Averaged by year, the highest was 12 ppb, in 2024: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 21.5 ppb. In 2026, the latest year on file, its two samples averaged 4.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 40.2 ppb, in 2017.
What handles it
- NSF/ANSI 58 look for “Uranium”
Arsenic
Comes from the source
1.3ppb
Highest yearly average, 2020 to 2023
Averaged by year, the highest was 1.3 ppb, in 2023: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 2.6 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 7.0 ppb, in 2014.
What handles it
- NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
- NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
Lead
Comes from pipes, often your own
1.4ppb
90th percentile, 2025
In the latest period, 9 in 10 homes sampled were at or below 1.4 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.
What handles it
- NSF/ANSI 53 look for “Lead Reduction”
- NSF/ANSI 58 look for “Lead Reduction”
Below EPA’s limits3
Haloacetic acids (HAA5)
Forms or is added in treatment
34.5ppb
Highest yearly average, 2020 to 2026
2026 average: 13 ppb
Averaged by year, the highest was 34.5 ppb, in 2022, below EPA’s legal limit of 60 ppb. Its highest single sample was 40 ppb. In 2026, the latest year on file, its two samples averaged 13 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.6 ppb, in 2017.
What handles it
No certification claim covers this compound yet.
Fluoride
Forms or is added in treatment
0.2ppm
Highest yearly average, 2020 to 2023
2023 average: 0.067 ppm
Averaged by year, the highest was 0.2 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. In 2023, the latest year on file, its three samples averaged 0.067 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.3 ppm, in 2014.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
Chromium (total)
Comes from the source
1.3ppb
Highest yearly average, 2020 to 2023
Averaged by year, the highest was 1.3 ppb, in 2023, below EPA’s legal limit of 100 ppb. Its highest single sample was 2.8 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 6.0 ppb, in 2014.
What handles it
- NSF/ANSI 58 look for “Chromium (Hexavalent) Reduction”
- NSF/ANSI 53 look for “Chromium Reduction”
What handles it
A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”
- NSF/ANSI 53
Claims: Nitrate/Nitrite (30 ppm challenge), Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction
For: Nitrate, Total trihalomethanes (TTHM), Arsenic, Lead
Other certifiers’ wording: VOC Reduction; Arsenic (III) (50 ppb influent level)
- NSF/ANSI 58
Claims: Nitrate/Nitrite Reduction, Trihalomethanes (TTHM) Reduction, Uranium, Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction
For: Nitrate, Total trihalomethanes (TTHM), Uranium, Arsenic, Lead
Other certifiers’ wording: Nitrate; Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)
At the tap, or for the whole house?
Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.
Filters with those claims on a certifier’s listing
Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money
Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Nitrate, Total trihalomethanes (TTHM), Arsenic, Lead
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Nitrate, Total trihalomethanes (TTHM), Arsenic, Lead
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Total trihalomethanes (TTHM), Arsenic, Lead
Culligan 10-Cup Pitcher with ZeroWater Technology (ZEROP10)
Pitcher
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 401checked Oct. 9, 2026
Certified for: Nitrate, Lead
Aquasana Clean Water Machine (AQ-CWM2)
Countertop
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 401checked Oct. 9, 2026
Certified for: Total trihalomethanes (TTHM), Lead
Hardness
Very hard, 596 mg/L (34.8 grains per gallon), at its one sampling point, 2020 to 2023.
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 |
|---|---|---|---|---|
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Oct. 1, 2021 to Dec. 31, 2021 | 20 MG/L | Archived |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Oct. 1, 2020 to Dec. 31, 2020 | 14 MG/L | Archived |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | April 1, 2020 to June 30, 2020 | 11 MG/L | Archived |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | July 1, 2019 to Sept. 30, 2019 | 12 MG/L | Archived |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | April 1, 2018 to June 30, 2018 | 15 MG/L | Archived |
| Nitrate | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | July 1, 2016 to Sept. 30, 2016 | 17 MG/L | Archived |
| 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, total trihalomethanes (TTHM), uranium, arsenic, haloacetic acids (HAA5), fluoride and chromium (total) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. San Lucas County Water 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 Jan. 7, 2020 to July 9, 2026.
Testing your own tap
The 3 labs California certifies closest to the area San Lucas County Water District serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Monterey County Consolidated Environmental Laboratory
Salinas, CA · about 55 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics
Monterey Bay Analytical Services, Inc.
Monterey, CA · about 58 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, radioactivity
County of San Luis Obispo Public Health Laboratory
San Luis Obispo, CA · about 61 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
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- 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 April 7, 2020 to Nov. 29, 2023, read Oct. 10, 2026
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID CA2701676. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Read up on the 5 results above a lineWhat each one does to health, where it comes from, and the certification claim that addresses it.Start with Nitrate
- Get the utility’s own reportSan Lucas County Water 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
- Compare certified filtersWhat the filters certified for these results cost over five years, cartridges included.Compare five-year costs