Golden State Water Company - Cypress Ridge
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
- 2,032 people
- Connections
- 971
- Water source
- Groundwater
- Based in
- Rancho Cordova, CA
- County
- San Luis Obispo
- Owner
- Private
- Hardness
- Varies by source
The ZIP code it serves
The short answer
4 results are above the health goal. The worst: Nitrate, above the health goal. No health-based violations on file since 2016.
What handles itWhat was found
Lead and copper: EPA SDWIS monitoring periods ending 2007 to 2028.
Nitrate, arsenic, uranium, chromium (total), total trihalomethanes (TTHM), haloacetic acids (HAA5) and fluoride: California’s own results, samples taken from Jan. 7, 2020 to July 14, 2026, with EPA’s 2012 to 2019 file for earlier years.
Above the health goal4
Nitrate
Comes from the source
17ppm
Highest sample; found in 3,103 of 3,103
2026 average: 6.7 ppm
From 2020 to 2026, 24 samples were above EPA’s legal limit of 10 ppm, the highest 17 ppm in 2023. The next sample at the same point, within 30 days, kept the average above the limit for 17; seven came back under. 10 ppm is also EPA’s health goal. In 2026, the latest year on file, its 251 samples averaged 6.7 ppm. EPA recorded no violation for nitrate at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 30 ppm, in 2019, and EPA recorded a violation in 2013.
What handles it
- NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
- NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
Arsenic
Comes from the source
3.9ppb
Highest yearly average, 2020 to 2026
Averaged by year, the highest was 3.9 ppb, in 2026: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 4.3 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.9 ppb, in 2012.
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
4.1ppb
90th percentile, 2026 to 2028
In the latest period, 9 in 10 homes sampled were at or below 4.1 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”
Uranium
Comes from the source
1.6ppb
Highest yearly average, 2020 to 2022
Averaged by year, the highest was 1.6 ppb, in 2022: below EPA’s legal limit of 30 ppb, but above its health goal of zero. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.6 ppb, in 2012.
What handles it
- NSF/ANSI 58 look for “Uranium”
Below EPA’s limits4
Chromium (total)
Comes from the source
52ppb
Highest yearly average, 2020 to 2026
2026 average: 3.3 ppb
Averaged by year, the highest was 52 ppb, in 2021, below EPA’s legal limit of 100 ppb. Its highest single sample was 260 ppb. In 2026, the latest year on file, its three samples averaged 3.3 ppb. EPA recorded no violation for chromium (total) at this utility since 2020.
What handles it
- NSF/ANSI 58 look for “Chromium (Hexavalent) Reduction”
- NSF/ANSI 53 look for “Chromium Reduction”
Total trihalomethanes (TTHM)
Forms or is added in treatment
10.3ppb
Highest yearly average, 2020 to 2026
Averaged by year, the highest was 10.3 ppb, in 2026, below EPA’s legal limit of 80 ppb. Its highest single sample was 24 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 7.3 ppb, in 2017.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
Haloacetic acids (HAA5)
Forms or is added in treatment
2.9ppb
Highest yearly average, 2020 to 2026
Averaged by year, the highest was 2.9 ppb, in 2026, below EPA’s legal limit of 60 ppb. Its highest single sample was 9.6 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.6 ppb, in 2013.
What handles it
No certification claim covers this compound yet.
Fluoride
Forms or is added in treatment
0.15ppm
Highest yearly average, 2020 to 2026
2026 average: 0.12 ppm
Averaged by year, the highest was 0.15 ppm, in 2025, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.2 ppm. In 2026, the latest year on file, its three samples averaged 0.12 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.15 ppm, in 2012.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
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), Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction
For: Nitrate, Arsenic, Lead
Other certifiers’ wording: Arsenic (III) (50 ppb influent level)
- NSF/ANSI 58
Claims: Nitrate/Nitrite Reduction, Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction, Uranium
For: Nitrate, Arsenic, Lead, Uranium
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, 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, 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
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, Lead
Hardness
Soft to very hard depending on the source, 39 to 260 mg/L (2.3 to 15.2 grains per gallon), across 11 sampling points, 2019 to 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.
Violations since 2016
No health-based violations on file with EPA since 2016.
What this report can’t tell you
Everything else. Nitrate, arsenic, uranium, chromium (total), total trihalomethanes (TTHM), haloacetic acids (HAA5) and fluoride results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Golden State Water Company - Cypress Ridge’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 14, 2026.
Testing your own tap
The 3 labs California certifies closest to the area Golden State Water Company - Cypress Ridge 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 12 miles
Certified for bacteria
Fruit Growers Laboratory, Inc.
San Luis Obispo, CA · about 12 miles
Certified for bacteria
Abalone Coast Analytical, Inc.
San Luis Obispo, CA · about 12 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 Feb. 5, 2019 to Jan. 29, 2026, read Oct. 10, 2026
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID CA4010040. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Read up on the 4 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 reportGolden State Water Company - Cypress Ridge 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