PWSID CA4300575
TWIN VALLEY INC
Community water system based in Castroville, CA
Service area on file with EPA: Santa Clara County. EPA's recorded service area can be incomplete for regional authorities. The cities and counties above are what the utility has filed with EPA; the utility may serve additional areas.
- Population served
- 317
- Source
- Groundwater
- Status
- Active
At a glance
1 finding worth watching
-
Public health experts agree no amount of lead in drinking water is safe. Even low levels can affect children's brain development.
Most recent lead and copper test · See details below
-
This utility's inventory reports no confirmed lead service lines and a low share of unclassified lines.
From the utility's published inventory · See details below
-
CDC's My Water's Fluoride listing does not report this system as fluoridating its drinking water.
Per CDC My Water's Fluoride · See details below
Past 5 years: 16 health-based violations on file, all marked Resolved or Archived. See compliance history below.
Risk classification follows EPA's published values for safe drinking water, with caution and concern bands reviewed by a clinician. Past resolved violations do not influence this card. See methodology.
Lead service line inventory
Utility reports no confirmed lead service lines
TWIN VALLEY INC reports 0 confirmed lead service lines, 84 non-lead, 0 unknown (total 84) in the EPA SDWIS service line inventory (2026Q1).
- 0 confirmed lead service lines
- 0 galvanized requiring replacement (LCRI treats these as lead)
- 0 unknown (0.0% of total)
- 84 confirmed non-lead (100.0%)
- 84 total service lines in the system
What to do if your service line might be lead
- Ask your utility to check the service-line classification for your specific address. Many utilities provide a public address-lookup tool linked from the inventory page.
- Get on the replacement queue. Under the LCRI, utilities must replace all lead and galvanized-requiring- replacement lines within 10 years (clock generally starts November 2027). Some prioritize requests.
- Until the line is replaced: flush the tap 30 seconds after long stagnation, use cold water for drinking and cooking, and consider an NSF/ANSI 53 lead-rated tap filter.
- Talk to your clinician about a blood lead test for anyone in the home, especially a pregnant person or a child under 6. Lead in drinking water guide.
Inventory data sourced from TWIN VALLEY INC ( retrieved May 24, 2026 ; curator confidence: high ). Confirmed against the original source automatically each month; see methodology.
Lead and copper test results
The most recent measurement per contaminant from EPA's Lead and Copper Rule sampling.
Why only lead and copper, and not arsenic, nitrate, or others?
EPA's bulk SDWIS download is the only nationwide per-system sample data they publish, and it only includes the Lead and Copper Rule table. Values for other regulated contaminants (TTHMs, nitrate, arsenic, etc.) appear on this page only when they trigger a violation. For the full per-system contaminant suite, see the utility's annual Consumer Confidence Report (link further down the page).
| Contaminant | Most recent | Date | Risk |
|---|---|---|---|
| PB90 | 0.0039 mg/L | December 31, 2025 | Caution |
Data from EPA SDWIS (Lead and Copper Rule sample table) , last refreshed May 24, 2026.
Fluoride
Per CDC My Water's Fluoride
TWIN VALLEY INC does not add fluoride to its drinking water.
This system has not reported adding fluoride to its water on CDC's My Water's Fluoride listing. Natural fluoride may still be present at trace levels from the source water; the utility's annual water quality report has the latest measured concentration.
Source: CDC My Water's Fluoride, listed under Twin Valley, Inc. (Santa Clara County). Verify on CDC's site .
Area context
Santa Clara County, CA (2020 data)
- Community water systems
- 28 of 123 add fluoride
- Population on fluoridated water
- 1,482,201 of 3,598,403 (41.2%)
California statewide (2020 data)
- Population on fluoridated water
- 21,879,582 of 38,051,212 (57.5%)
- Community water systems adding fluoride
- 417 of 3,057
Data from CDC My Water's Fluoride (per-system status) , last refreshed May 19, 2026.
Data from CDC Water Fluoridation Reporting System (state and county aggregates) , last refreshed May 16, 2026.
Recorded contaminant measurements (from violations)
When this system exceeded a regulatory limit and EPA recorded the measured value, that value is shown here. These are not routine sample results: they are the values the violation was triggered on.
| Period | Contaminant | Measured | Federal MCL | Status |
|---|---|---|---|---|
| November 1, 2023 | Nitrate | 10.5MG/L | 10 MG/L | Health-based |
| July 1, 2023 | Nitrate | 10.6MG/L | 10 MG/L | Health-based |
| June 1, 2023 | Nitrate | 10.5MG/L | 10 MG/L | Health-based |
| November 1, 2022 | Nitrate | 10.6MG/L | 10 MG/L | Health-based |
| October 1, 2022 | Nitrate | 10.7MG/L | 10 MG/L | Health-based |
| September 1, 2022 | Nitrate | 11MG/L | 10 MG/L | Health-based |
| August 1, 2022 | Nitrate | 10.7MG/L | 10 MG/L | Health-based |
| July 1, 2022 | Nitrate | 10.8MG/L | 10 MG/L | Health-based |
| May 1, 2022 | Nitrate | 10.5MG/L | 10 MG/L | Health-based |
| December 1, 2021 | Nitrate | 10.8MG/L | 10 MG/L | Health-based |
| November 1, 2021 | Nitrate | 11.1MG/L | 10 MG/L | Health-based |
| October 1, 2021 | Nitrate | 10.8MG/L | 10 MG/L | Health-based |
| September 1, 2021 | Nitrate | 11.3MG/L | 10 MG/L | Health-based |
| August 1, 2021 | Nitrate | 11.3MG/L | 10 MG/L | Health-based |
| July 1, 2021 | Nitrate | 11.4MG/L | 10 MG/L | Health-based |
| June 1, 2021 | Nitrate | 11.6MG/L | 10 MG/L | Health-based |
Data from EPA SDWIS (violation records) , last refreshed May 24, 2026.
Compliance history
EPA-recorded violations against this system over the last 5 years.
How to read this section
Health-based violations are when a measured limit was exceeded; the measured concentration is shown alongside the EPA federal limit where SDWIS published it. Monitoring and reporting items are paperwork issues (missed sample dates, late filings) that do not themselves indicate unsafe water.
16 resolved health-based violations in the last 5 years
All 16 health-based violations in the last 5 years are marked Resolved or Archived. Past violations do not represent current water quality.
| Period start | Contaminant | What happened | Measured level | Status |
|---|---|---|---|---|
| November 1, 2023 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.50 MG/L
MCL 10 MG/L | Resolved |
| July 1, 2023 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.60 MG/L
MCL 10 MG/L | Resolved |
| June 1, 2023 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.50 MG/L
MCL 10 MG/L | Resolved |
| November 1, 2022 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.60 MG/L
MCL 10 MG/L | Resolved |
| October 1, 2022 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.70 MG/L
MCL 10 MG/L | Resolved |
| September 1, 2022 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11 MG/L
MCL 10 MG/L | Resolved |
| August 1, 2022 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.70 MG/L
MCL 10 MG/L | Resolved |
| July 1, 2022 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.80 MG/L
MCL 10 MG/L | Resolved |
| May 1, 2022 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.50 MG/L
MCL 10 MG/L | Resolved |
| December 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.80 MG/L
MCL 10 MG/L | Resolved |
| November 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.10 MG/L
MCL 10 MG/L | Resolved |
| October 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.80 MG/L
MCL 10 MG/L | Resolved |
| September 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.30 MG/L
MCL 10 MG/L | Resolved |
| August 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.30 MG/L
MCL 10 MG/L | Resolved |
| July 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.40 MG/L
MCL 10 MG/L | Resolved |
| June 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.60 MG/L
MCL 10 MG/L | Resolved |
47 older violation s (5-10 years ago) · 38 health-based, 9 paperwork , all resolved
| Period start | Relates to | Item | Measured level | Status |
|---|---|---|---|---|
| May 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.50 MG/L
MCL 10 MG/L | Resolved |
| April 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.60 MG/L
MCL 10 MG/L | Resolved |
| March 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.40 MG/L
MCL 10 MG/L | Resolved |
| February 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.70 MG/L
MCL 10 MG/L | Resolved |
| January 1, 2021 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.90 MG/L
MCL 10 MG/L | Resolved |
| December 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 12.10 MG/L
MCL 10 MG/L | Resolved |
| November 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.80 MG/L
MCL 10 MG/L | Resolved |
| October 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.50 MG/L
MCL 10 MG/L | Resolved |
| August 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 12 MG/L
MCL 10 MG/L | Resolved |
| July 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.80 MG/L
MCL 10 MG/L | Resolved |
| June 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.70 MG/L
MCL 10 MG/L | Resolved |
| May 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.50 MG/L
MCL 10 MG/L | Resolved |
| April 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.50 MG/L
MCL 10 MG/L | Resolved |
| March 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.70 MG/L
MCL 10 MG/L | Resolved |
| February 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.60 MG/L
MCL 10 MG/L | Resolved |
| January 1, 2020 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 12 MG/L
MCL 10 MG/L | Resolved |
| December 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.50 MG/L
MCL 10 MG/L | Resolved |
| November 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.90 MG/L
MCL 10 MG/L | Resolved |
| October 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.80 MG/L
MCL 10 MG/L | Resolved |
| September 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.30 MG/L
MCL 10 MG/L | Resolved |
| August 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.50 MG/L
MCL 10 MG/L | Resolved |
| July 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.90 MG/L
MCL 10 MG/L | Resolved |
| June 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.10 MG/L
MCL 10 MG/L | Resolved |
| May 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.50 MG/L
MCL 10 MG/L | Resolved |
| January 1, 2019 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 12 MG/L
MCL 10 MG/L | Resolved |
| December 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.37 MG/L
MCL 10 MG/L | Resolved |
| November 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 12.10 MG/L
MCL 10 MG/L | Resolved |
| October 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.80 MG/L
MCL 10 MG/L | Resolved |
| September 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.80 MG/L
MCL 10 MG/L | Resolved |
| August 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.60 MG/L
MCL 10 MG/L | Resolved |
| July 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.20 MG/L
MCL 10 MG/L | Resolved |
| June 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.60 MG/L
MCL 10 MG/L | Resolved |
| May 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.40 MG/L
MCL 10 MG/L | Resolved |
| April 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11 MG/L
MCL 10 MG/L | Resolved |
| March 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 10.70 MG/L
MCL 10 MG/L | Resolved |
| February 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 12.20 MG/L
MCL 10 MG/L | Resolved |
| February 1, 2018 | Revised Total Coliform Rule | Monitoring, Routine (RTCR) | — | Resolved |
| February 1, 2018 | Revised Total Coliform Rule | Monitoring, Routine (RTCR) | — | Resolved |
| January 1, 2018 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 12.10 MG/L
MCL 10 MG/L | Resolved |
| December 1, 2017 | Nitrate | Maximum Contaminant Level Violation, Single Sample | 11.50 MG/L
MCL 10 MG/L | Resolved |
| September 1, 2017 | Revised Total Coliform Rule | Monitoring, Routine (RTCR) | — | Resolved |
| August 1, 2017 | Revised Total Coliform Rule | Monitoring, Routine (RTCR) | — | Resolved |
| February 1, 2017 | Revised Total Coliform Rule | Monitoring, Routine (RTCR) | — | Resolved |
| July 15, 2016 | — | Variance/Exemption/Other Compliance | — | Resolved |
| July 15, 2016 | — | Variance/Exemption/Other Compliance | — | Resolved |
| June 30, 2016 | — | Variance/Exemption/Other Compliance | — | Resolved |
| June 30, 2016 | — | Variance/Exemption/Other Compliance | — | Resolved |
Data from EPA SDWIS (violation records) , last refreshed May 24, 2026.
Where to see every contaminant this utility tested for
EPA's bulk SDWIS dataset gives MyTapWater.us per-system measured values for lead and copper, plus violation records for everything else. To see every regulated contaminant this utility tested for in the past year (TTHMs, HAA5, nitrate, arsenic, fluoride, chromium, etc.) with measured values, read the utility's Consumer Confidence Report (CCR).
Every community water system is required by EPA to publish a CCR annually, by July 1, listing every contaminant they sampled, the measured value, the federal limit, and any health-based exceedances. Most utilities post the report online; some mail it with your bill.
How to find TWIN VALLEY INC's CCR:
- Search the web for "TWIN VALLEY INC consumer confidence report" . The PDF is usually on the utility's own website.
- Or call the utility directly. Their phone number is in the contact section below.
Other water systems in Santa Clara County, CA
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Contact this utility
Public administrative contact information for this water system, as filed with the EPA. Use this to ask about your service line, request your home's lead status, or report a water quality issue.
- Administrator
- FARMER, MILES
- Phone
- 831-920-6796
- Mailing address
- P.O. Box 615CASTROVILLE, CA 95012
Where this page's data comes from
Bundle released 2026-Q2, regenerated May 24, 2026. Each section above also shows its own source date so you can tell at a glance how fresh that part of the page is.
- EPA SDWIS bulk download — last refreshed May 24, 2026 (system info, violations, lead and copper samples).
- Lead service line inventory — last refreshed May 24, 2026 (from the utility's reported inventory).
- CDC My Water's Fluoride — last refreshed May 19, 2026 (per-system Yes/No fluoridation status).
- CDC Water Fluoridation Reporting System — last refreshed May 16, 2026 (state and county fluoridation aggregates).
Every value on this page is cross-verified before publication; read our methodology for the verification steps and corrections process.