Resthaven Mobile Home Park
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
- 99 people
- Connections
- 80
- Water source
- Groundwater
- Based in
- Paso Robles, CA
- County
- San Luis Obispo
- Owner
- Private
- Hardness
- Very hard
The ZIP code it serves
The short answer
2 results are above the health goal. The worst: Arsenic, above the health goal. 22 health-based violations since 2016.
What handles itWhat was found
Arsenic, uranium, fluoride, total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5) and chromium (total): California’s own results, samples taken from March 2, 2020 to April 23, 2026, with EPA’s 2012 to 2019 file for earlier years.
Above the health goal2
Arsenic
Comes from the source
10.1ppb
Highest yearly average, 2021 to 2025
Averaged by year, the highest was 10.1 ppb, in 2025, which EPA rounds to 10 ppb to compare: at its legal limit of 10 ppb, not above it. Its highest single sample was 12 ppb. That was also the latest year on file. EPA recorded no violation for arsenic at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 6.0 ppb, in 2013.
What handles it
- NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
- NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
Uranium
Comes from the source
10.9ppb
Highest yearly average, 2025 to 2026
2026 average: 8.9 ppb
Averaged by year, the highest was 10.9 ppb, in 2025: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 13 ppb. In 2026, the latest year on file, its two samples averaged 8.9 ppb.
What handles it
- NSF/ANSI 58 look for “Uranium”
Below EPA’s limits5
Fluoride
Forms or is added in treatment
0.49ppm
Highest yearly average, 2021 to 2025
2025, one sample: 0.3 ppm
Averaged by year, the highest was 0.49 ppm, in 2021, below EPA’s legal limit of 4.0 ppm. In 2025, the latest year on file, its one sample was 0.3 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.58 ppm, in 2018.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
Total trihalomethanes (TTHM)
Forms or is added in treatment
8.7ppb
Highest yearly average, 2020 to 2023
Averaged by year, the highest was 8.7 ppb, in 2023, below EPA’s legal limit of 80 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 27 ppb, in 2017.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
Nitrate
Comes from the source
0.5ppm
Highest sample; found in 6 of 17
2026: not found
The highest sample, in 2025, was 0.5 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.63 ppm, in 2012.
What handles it
- NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
- NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
Haloacetic acids (HAA5)
Forms or is added in treatment
2.6ppb
Highest yearly average, 2020 to 2023
2023: not found
Averaged by year, the highest was 2.6 ppb, in 2020, below EPA’s legal limit of 60 ppb. In 2023, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 8.5 ppb, in 2017.
What handles it
No certification claim covers this compound yet.
Chromium (total)
Comes from the source
3.4ppb
Highest yearly average, 2021 to 2025
Averaged by year, the highest was 3.4 ppb, in 2025, below EPA’s legal limit of 100 ppb. That was also the latest year on file.
What handles it
- NSF/ANSI 58 look for “Chromium (Hexavalent) Reduction”
- NSF/ANSI 53 look for “Chromium Reduction”
One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Lead
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
Claim: Arsenic (Pentavalent)<=50 ppb Reduction
For: Arsenic
Other certifiers’ wording: Arsenic (III) (50 ppb influent level)
- NSF/ANSI 58
Claims: Arsenic (Pentavalent)<=50 ppb Reduction, Uranium
For: Arsenic, Uranium
Other certifiers’ wording: Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)
At the tap, or for the whole house?
These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. 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: Arsenic
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: Arsenic
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: Arsenic
Hardness
Very hard, typically 621 mg/L (36.3 grains per gallon), across 2 sampling points, 2019 to 2025.
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 |
|---|---|---|---|---|
| Selenium | 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, 2026 to June 30, 2026 | 150 UG/L | Archived |
| Selenium | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | March 1, 2026 to May 31, 2026 | 150 UG/L | Archived |
| Selenium | 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, 2025 to Dec. 31, 2025 | 150 UG/L | Archived |
| Selenium | 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, 2025 to Sept. 30, 2025 | 150 UG/L | Archived |
| Selenium | 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, 2025 to June 30, 2025 | 140 UG/L | Archived |
| Selenium | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2025 to March 31, 2025 | 190 UG/L | Archived |
| Selenium | 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, 2024 to Dec. 31, 2024 | 400 UG/L | Archived |
| Selenium | 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, 2024 to Sept. 30, 2024 | 180 UG/L | Archived |
| Selenium | 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, 2024 to June 30, 2024 | 180 UG/L | Archived |
| Selenium | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2024 to March 31, 2024 | 260 UG/L | Archived |
| Selenium | 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, 2023 to Dec. 31, 2023 | 270 UG/L | Archived |
| Selenium | 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, 2023 to Sept. 30, 2023 | 270 UG/L | Archived |
| Selenium | 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, 2023 to June 30, 2023 | 140 UG/L | Archived |
| Selenium | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2023 to March 31, 2023 | 41 UG/L | Archived |
| Selenium | 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, 2022 to Dec. 31, 2022 | 76 UG/L | Archived |
| Selenium | 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, 2022 to Sept. 30, 2022 | 76 UG/L | Archived |
| Selenium | 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, 2022 to June 30, 2022 | 60 UG/L | Archived |
| Selenium | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | Jan. 1, 2022 to March 31, 2022 | 55 UG/L | Archived |
| Selenium | 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 | 55 UG/L | Archived |
| Selenium | 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, 2021 to Sept. 30, 2021 | 73 UG/L | Archived |
| Selenium | A sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single Sample | April 5, 2021 to July 4, 2021 | 64 UG/L | Archived |
| Selenium | 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 | 58 UG/L | Archived |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. | ||||
What this report can’t tell you
Everything else. Arsenic, uranium, fluoride, total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5) and chromium (total) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Resthaven Mobile Home Park’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 March 2, 2020 to April 23, 2026.
Testing your own tap
The 3 labs California certifies closest to the area Resthaven Mobile Home Park serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
County of San Luis Obispo Public Health Laboratory
San Luis Obispo, CA · about 27 miles
Certified for bacteria
Fruit Growers Laboratory, Inc.
San Luis Obispo, CA · about 29 miles
Certified for bacteria
Abalone Coast Analytical, Inc.
San Luis Obispo, CA · about 29 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 Dec. 2, 2019 to Dec. 11, 2025, read Oct. 10, 2026
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID CA4000654. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Read up on the 2 results above a lineWhat each one does to health, where it comes from, and the certification claim that addresses it.Start with Arsenic
- Get the utility’s own reportResthaven Mobile Home Park 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