Skip to main content
WaterVerge

Water quality report · updated Jul 2026

Is Redwood Valley, CA Tap Water Safe to Drink?

Graded C, with 16 unresolved violations on record. See what was cited — and what it means for your tap. What to do ↓

0 contaminants over a legal limit
5.0 ppb lead, 90th percentile · low
16 unresolved violations
1K people served by 3 water systems

PWSID 090600030 · moderate data confidence · native american utility

Reviewed by WaterVerge Editorial Team · Last updated July 2026
C 64.1 / 100

#551 of 690California cities
How we grade →

01The verdict: is Redwood Valley water safe?

Redwood Valley's drinking water has significant quality concerns based on EPA testing data. With a grade of C (64.1/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 1,092 residents using surface water (rivers, lakes, or reservoirs).

The concern

16 unresolved violations on record

EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.

See what was cited ↓
The good news

Lead is well under the limit

90th-percentile lead is 5.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.

See the trend ↓
Keep watching

23 violations in the last five years

Recent compliance history is the best predictor of future problems — the year-by-year record is below.

See the record ↓

Redwood Valley's drinking water received a grade of C (64.1 out of 100), indicating fair water quality. The city's 3 water systems serve approximately 1,092 residents using purchased surface water.

Lead levels were measured at 5.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 76 violations on record, including 2 health-based violations. 16 remain unresolved.

Redwood Valley ranks #551 out of 690 cities in California for water quality, placing it among the lowest-rated in the state. The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection. As a small community water system, Redwood Valley may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities. The system has seen 23 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.

How the 64.1/100 breaks down Methodology →
ViolationsHistorical violation record including health-based and monitoring violations.
20.1 / 45F
Lead & CopperLead at 5.0 ppb (90th percentile).
18 / 20A
ContaminantsPFAS + legacy contaminant analysis.
17 / 20B
ComplianceMonitoring and reporting compliance with EPA regulations.
5 / 10D
Source RiskWater source: Purchased surface water.
4 / 5B

02What's in Redwood Valley's water

Every contaminant flagged in Redwood Valley, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.

1 detection · sorted by % of legal limit
Over the limit Elevated — watch Within limits
0 50% LEGAL LIMIT 150%
1 contaminant tested under EPA SDWIS, LCR and UCMR programs · 1 detected · not yet tested for PFAS under UCMR 5

Full contaminants report

Contaminant Detected Level EPA Limit Unit Category Status
Lead (90th percentile) 5.0 15 ppb Inorganic Safe
Data source: EPA SDWIS, UCMR 5, local utility CCR.

03Redwood Valley's ten-year track record

Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 76 violations on record, including 2 health-based violations. 16 remain unresolved.

2 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.

1 health-based in 10 yrs 26 monitoring & paperwork 5 still unresolved
UpdateWater quality data updatedLatest EPA compliance and testing data incorporated into Redwood Valley's water quality assessment. Grade: C (64.1/100).
Violation1 drinking water violation recordedContaminants: Revised Total Coliform Rule.Resolved
Violation1 drinking water violation recordedContaminants: Chlorine.Resolved
Violation2 drinking water violations recordedContaminants: Arsenic, Toluene.Resolved
DisasterSEVERE WINTER STORMS, FLOODING, LANDSLIDES, AND MUDSLIDESFederal disaster declaration (FEMA DR-3592). Flood event — may have impacted local water infrastructure.
DisasterSEVERE WINTER STORMS, FLOODING, LANDSLIDES, AND MUDSLIDESFederal disaster declaration (FEMA DR-4683). Flood event — may have impacted local water infrastructure.
Lead, 90th percentileppb · lower is better
05101520EPA action level · 15 ppb1995 — 0 ppb1996 — 0 ppb1998 — 5 ppb2003 — 0 ppb2004 — 0 ppb2005 — 6 ppb2007 — 6 ppb2008 — 5 ppb2009 — 11 ppb2013 — 5 ppb2016 — 4 ppb2017 — 0 ppb2018 — 0 ppb2019 — 5 ppb2022 — 5 ppb2023 — 3.4 ppb2024 — 5 ppb2025 — 5 ppb5199520042009201820242025

Up 5 ppb since 1995. Latest reading: 5 ppb (2025) — 33% of the action level. Sampled at higher-risk homes (90th percentile).

04Where Redwood Valley's water comes from

Redwood Valley's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.

Source

Purchased Surface Water

Rivers, lakes, or reservoirs — more exposed to runoff, agriculture, and seasonal swings than groundwater.

Treatment

Wholesale supplier

Multi-barrier treatment: coagulation, sedimentation, filtration, and disinfection to meet EPA standards.

Distribution

3 systems

3 water systems, operated under native american ownership.

Delivery

1,092 people

Residents served across Redwood Valley's service area.

Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards. These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge. The system is operated by native american ownership and serves approximately 1,092 people through 3 water systems.

System namePWSIDPopulationSource
Coyote Valley System 090600030 850 Purchased Surface Water
Redwood Valley Rancheria 090605118 152 Purchased Surface Water
LAKE VIEW MUTUAL WATER CO. CA2300606 90 Groundwater

Water bodies near Redwood Valley

Ef Russian R Nr Calpella · river

As a surface-water system, these water bodies may directly influence Redwood Valley's drinking water supply.

05Pressure on Redwood Valley's watershed

Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.

Industrial discharge

Present — monitored

1 facility within 10 miles reported 0 lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed.

MENDOCINO FOREST PRODUCTS CO. LLC 0 lb · 6.3 mi

Flood & storm history

Recurring — declared disasters

10 federal disaster declarations on record for Mendocino County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.

SEVERE WINTER STORMS, FLOODING, LANDSLIDES, AND MUDSLIDES Mar 2023 · DR-3592
SEVERE WINTER STORMS, FLOODING, LANDSLIDES, AND MUDSLIDES Jan 2023 · DR-4683
SEVERE WINTER STORMS, FLOODING, AND MUDSLIDES Jan 2023 · DR-3591

06How Redwood Valley compares

Scores for nearby California cities on one line, with the average marked.

Oakland
77.9 · B
Redwood Valley (this city)
64.1 · C
Los Angeles
42.8 · F
San Diego
39.7 · F
Sacramento
31.2 · F
San Jose
28 · F

dashed line = California average (57/100)

Redwood Valley scores 64.1/100above the California average of 57/100. It outscores 5 of 10 nearby cities. Full California rankings →

Mendocino water quality rankings
Compare all cities in the county — grades, violations, and contaminant data side by side.

07What to do at home

Steps matched to what testing actually found in Redwood Valley's water — not generic advice.

Extra protection

A basic carbon filter still helps

Redwood Valley's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.

Compare tested filters →
Because lead was detected

Flush taps & check your service line

Lead leaches from pipes as water sits. Run cold water 30 seconds before drinking (especially mornings), and ask the utility whether your address still has a lead service line.

Lead risks explained →
Stay informed

Watch for Redwood Valley alerts

This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.

All water alerts →

Frequently asked questions

Is Redwood Valley, CA tap water safe to drink?

Redwood Valley's water quality earned a grade of C (64.1/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #551 out of 690 cities tested in California.

What contaminants are in Redwood Valley's water?

Lead was measured at 5.0 ppb (90th percentile). 76 violations are on record.

How is Redwood Valley's water quality grade calculated?

The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.

Do I need a water filter in Redwood Valley?

Based on current data, basic filtration should suffice for additional peace of mind.

Where does Redwood Valley's water come from?

Redwood Valley's water is sourced from Purchased surface water. The city has 3 water systems serving approximately 1,092 residents.

What health violations has Redwood Valley's water system had?

Redwood Valley has 2 health-based violations on record. The most recent violation was recorded in December 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 16 violations remain unresolved.

How does Redwood Valley's water compare to other cities?

Redwood Valley ranks #551 out of 690 cities in California (better than 20% of state cities) and #11506 out of 15382 cities nationally (25th percentile). The grade of C reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.

Share this reportHelp others learn about their water quality
WhatsAppXFacebookLinkedInEmail
About Redwood Valley, CA: Redwood City is a city in San Mateo County, California, on the San Francisco Peninsula in the Bay Area of Northern California, approximately 27 miles (43 km) south of San Francisco and 24 miles (39 km) northwest of San Jose. The city's population was 84,292 according to the 2020 census. The Port of Redwood City is the only deepwater port on San Francisco Bay south of San Francisco. Median household income $53,600 · median home value $553,210 · median age 43.4 · 51% homeowners · 14.2% college educated. Wikipedia → Service area: 2 ZIP codes across Mendocino.
Show ZIP codes 9547095470-0039
Sources: EPA SDWIS & ECHO · UCMR 3–5 · Lead & Copper Rule samples · EPA TRI · U.S. Drought Monitor · FEMA declarations. Data last updated Jul 2026. Analysis by the WaterVerge Editorial Team · methodology.