Tamalpais Union High School District (CA): 3 Health Violations
23 ZIP codes · 18 water systems · 3,072,352 people served · Updated 2026-07-23
ZipCheckup's reading of EPA drinking-water data for Tamalpais Union High School District: 6 unresolved violations in the water systems serving this district.
Data: EPA SDWIS, NCES Last verified: 2026-07-23
Why School Water Quality Matters
Children drink 2–4× more water per pound of body weight than adults, making them more vulnerable to contaminants. School water quality affects students for hours every weekday.
Water Quality Overview
The Tamalpais Union High School District in California spans 23 ZIP codes served by 18 community water systems, providing water to approximately 3,072,352 people.
The average Home Safety Score across the district is C (69/100)
- with the lowest-scoring area at 55/100 .
Water quality in this district ranks better than 52% of ZIP codes nationally.
Why This Matters for Children
Children are more vulnerable to water contaminants than adults. The EPA and CDC identify these key risks:
- Lead exposure - Even low levels of lead can affect brain development, reduce IQ, and cause behavioral problems in children. There is no safe level of lead for children.
- PFAS ("forever chemicals") - Linked to immune system effects and developmental delays in children. Children drink more water relative to body weight than adults.
- Nitrate - Dangerous for infants (can cause "blue baby syndrome"). Agricultural areas often have elevated nitrate.
- Disinfection byproducts - Long-term exposure may increase cancer risk. School water fountains often have stagnant water that concentrates these compounds.
Lead Levels in the District
| Metric | Value | EPA Threshold |
|---|---|---|
| Average lead level (90th percentile) | 0.006 mg/L | 0.015 mg/L |
| Highest lead level | 0.013 mg/L | 0.015 mg/L |
| ZIP codes exceeding EPA action level | 0 of 23 | - |
EPA Violation History
Contaminants of Concern
| Contaminant | Category | Violations | Health-Based | ZIPs Affected |
|---|---|---|---|---|
| Stage 2 DBP Rule | Treatment Technique | 4 | Yes | 2 |
| Barium | Inorganic | 1 | No | 1 |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 1 | Yes | 1 |
| Stage 1 DBP Rule | Treatment Technique | 1 | No | 1 |
| Consumer Confidence Report Rule | Reporting | 1 | No | 1 |
Radon Risk
Dominant radon zone: Zone 3 (Low risk)
Water Quality by ZIP Code
| ZIP Code | City | Safety Score | Violations | Health | Lead Level | Exceeds? |
|---|---|---|---|---|---|---|
| 94947 | Novato | C (56) | 2 | 1 | 0.013 mg/L | No |
| 94952 | Petaluma | B (76) | 2 | 1 | 0.00043 mg/L | No |
| 94904 | Greenbrae | B (78) | 1 | 0 | 0.0008 mg/L | No |
| 94939 | Larkspur | B (79) | 1 | 0 | 0.00756 mg/L | No |
| 94946 | Nicasio | A (94) | 1 | 1 | 0.004 mg/L | No |
| 94970 | Stinson Beach | B (75) | 1 | 0 | — | — |
| 94901 | San Rafael | C (55) | 0 | 0 | — | — |
| 94903 | San Rafael | C (55) | 0 | 0 | — | — |
| 94920 | Belvedere Tiburon | C (60) | 0 | 0 | — | — |
| 94924 | Bolinas | B (80) | 0 | 0 | 0.009 mg/L | No |
| 94925 | Corte Madera | B (77) | 0 | 0 | — | — |
| 94930 | Fairfax | C (60) | 0 | 0 | — | — |
| 94933 | Forest Knolls | C (65) | 0 | 0 | — | — |
| 94938 | Lagunitas | B (73) | 0 | 0 | — | — |
| 94941 | Mill Valley | C (55) | 0 | 0 | — | — |
| 94950 | Olema | B (73) | 0 | 0 | — | — |
| 94956 | Point Reyes Station | B (78) | 0 | 0 | 0.008 mg/L | No |
| 94957 | Ross | C (55) | 0 | 0 | — | — |
| 94960 | San Anselmo | C (55) | 0 | 0 | — | — |
| 94963 | San Geronimo | B (73) | 0 | 0 | — | — |
| 94964 | San Quentin | C (66) | 0 | 0 | — | — |
| 94965 | Sausalito | A (85) | 0 | 0 | 0.0052 mg/L | No |
| 94973 | Woodacre | B (73) | 0 | 0 | — | — |
Water Systems Serving This District
| Water System | Population Served | Source | ZIP Codes |
|---|---|---|---|
| Marin Municipal Water District | 186,895 | Surface water | 94901, 94903, 94904 +13 more |
| NORTH MARIN WATER DISTRICT | 61,691 | Surface water | 94903, 94924, 94946 +3 more |
| City of Petaluma, | 60,781 | Groundwater | 94952 |
| City of Rohnert Park, | 43,821 | Groundwater | 94952 |
| NPS GGNRA | 18,447 | Surface water | 94920, 94941, 94965 |
| City of Cotati, | 7,303 | Groundwater | 94952 |
| Bolinas Community Pud | 2,483 | Surface water | 94924, 94970 |
| North Marin Water District - Pt. Reyes | 1,841 | Groundwater | 94947 |
18 water systems total serve this district.
Lead Risk Assessment
Infrastructure Risk Factors
| Risk Factor | District Average | Why It Matters |
|---|---|---|
| Housing built before 1986 | 83.3% | Lead solder was used in plumbing until 1986 |
| Housing built before 1950 | 30% | Lead pipes were common before 1950 |
| Lead service line probability | 24.1% | Estimated chance of lead pipes connecting homes to water mains |
| Average lead level (90th pctl) | 0.006 mg/L | EPA action level: 0.015 mg/L |
| Highest measured lead level | 0.013 mg/L | EPA action level: 0.015 mg/L |
Schools built before 1986 are especially at risk. Lead can leach from older pipes, fixtures, and solder joints into drinking water — particularly when water sits in pipes overnight or over weekends.
Detailed Violation History
| Contaminant | Category | Total Violations | Health-Based | ZIPs Affected |
|---|---|---|---|---|
| Stage 2 DBP Rule | Treatment Technique | 4 | Yes | 2 |
| Stage 1 DBP Rule | Treatment Technique | 1 | No | 1 |
| Consumer Confidence Report Rule | Reporting | 1 | No | 1 |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 1 | Yes | 1 |
| Barium | Inorganic | 1 | No | 1 |
Most Recent Violations
- Violation in ZIP 94904 (Unknown date) — Unresolved
- Violation in ZIP 94939 (Unknown date) — Unresolved
- Violation in ZIP 94947 (Unknown date) — Unresolved
- Violation in ZIP 94947 (Unknown date) — Unresolved
- Violation in ZIP 94952 (Unknown date) — Unresolved
Is the Water Safe at Tamalpais Union High School District Schools?
Several factors warrant attention for families in the Tamalpais Union High School District area:
- Water systems in this district have recorded 3 health-based violations. These violations indicate contaminant levels that may pose health risks.
- 83.3% of buildings in this district predate 1986, increasing the risk of lead in school plumbing.
- 6 violations remain unresolved, meaning the issues have not been officially corrected.
Important context: EPA compliance data measures water quality at the utility level. Individual school buildings — especially older ones — may have additional risks from internal plumbing, lead fixtures, and stagnant water in pipes.
What Parents Should Do
Testing
- Request your school's water testing results. Under the EPA's 3Ts program, schools are encouraged to test drinking water. Ask the Tamalpais Union High School District school board for the most recent results.
- Test your home water. If your home was built before 1986, lead may be present in your plumbing. Free or low-cost test kits are often available from your water utility.
Advocacy
- Attend school board meetings and ask about the district's water quality testing schedule and remediation plans.
- Request lead fixture replacement if your child's school was built before 1986 and hasn't upgraded its plumbing.
- Contact your water utility about the 6 unresolved violations in the district. Ask for a timeline for resolution.
Resources
ZIP Code Reports for This District
- 94947 — Novato (Grade: C), 2 violations
- 94952 — Petaluma (Grade: B), 2 violations
- 94904 — Greenbrae (Grade: B), 1 violation
- 94939 — Larkspur (Grade: B), 1 violation
- 94946 — Nicasio (Grade: A), 1 violation
- 94970 — Stinson Beach (Grade: B), 1 violation
- 94901 — San Rafael (Grade: C), no violations
- 94903 — San Rafael (Grade: C), no violations
- 94920 — Belvedere Tiburon (Grade: C), no violations
- 94924 — Bolinas (Grade: B), no violations
- 94925 — Corte Madera (Grade: B), no violations
- 94930 — Fairfax (Grade: C), no violations
- 94933 — Forest Knolls (Grade: C), no violations
- 94938 — Lagunitas (Grade: B), no violations
- 94941 — Mill Valley (Grade: C), no violations
- 94950 — Olema (Grade: B), no violations
- 94956 — Point Reyes Station (Grade: B), no violations
- 94957 — Ross (Grade: C), no violations
- 94960 — San Anselmo (Grade: C), no violations
- 94963 — San Geronimo (Grade: B), no violations
- ...and 3 more ZIP codes. See the full table above.
What Parents Can Do
- Request lead testing at your child's school - The EPA's 3Ts program (Training, Testing, Taking Action) provides guidance for schools. Ask your school board about their water testing schedule.
- Review the Consumer Confidence Report (CCR) - Your water utility publishes this annually. It details all detected contaminants.
- Consider a water filter for your home - NSF/ANSI 53 or NSF/ANSI 58 (reverse osmosis) filters are certified to remove lead. This is especially important for infant formula preparation.
- Pack water from home - If you're concerned about school water quality, send your child with a water bottle filled at home (filtered if possible).
- Stay informed - Bookmark this page to check for updates on water quality in your school district.
Need help with school water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
Frequently Asked Questions
Is the water safe in Tamalpais Union High School District schools?
Water systems serving Tamalpais Union High School District have recorded 3 health-based violations in the past 5 years. While utilities are required to meet federal standards, individual school buildings may have older plumbing that can introduce contaminants. Parents should request lead testing results from their school.
Does Tamalpais Union High School District test for lead in school water?
Federal law does not require schools to test for lead in drinking water (except in some states with specific mandates). The EPA's voluntary 3Ts program encourages testing. Contact your school district office to ask about their testing schedule and results.
What level of lead is safe for children?
There is no safe level of lead for children, according to the CDC. The EPA action level of 0.015 mg/L (15 ppb) triggers corrective action for water systems, but the American Academy of Pediatrics recommends that school water contain no more than 0.001 mg/L (1 ppb).
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- School districts: NCES EDGE Geographic Relationship Files
- Radon: EPA Map of Radon Zones
Updated daily.