Mill Valley flood history
1,517 days with roads at risk since 1996
Record high water
8.38 ft
Feb 6, 1998 · 23 roads at risk
Days a year, then vs now
40 → 61
1996–2005 vs 2016–2025
Most recent
Sep 30, 2026
7.19 ft · 9 roads at risk
On the map
The biggest days
Feb 6, 1998: 23 roads at risk8.38 ft at the San Francisco gauge · 2.2 ft above the tide tables · deepest: Severe · model estimate
Estimates, not records of actual flooding. Each day is NOAA's verified high water at the tide gauge, run through FloodRoute's flood model on today's roads and elevations, in dry weather. Drains, levees, tide gates, rain, road changes and elevation error all mean real conditions differed. Not for property, real-estate, insurance, lending, engineering or legal decisions.
1996–2026
Days with roads at risk, by year
Since 1996
Highest water
| Date | High water · San Francisco | vs tide tables | Roads at risk | Deepest streets (model) |
|---|---|---|---|---|
| 8.38 ft | +2.21 ft | 23Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.38 ft | +1.25 ft | 23Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.14 ft | +1.22 ft | 18Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.12 ft | +1.01 ft | 18Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.12 ft | +1.05 ft | 18Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.09 ft | +1.13 ft | 14Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.09 ft | +0.92 ft | 14Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.07 ft | +0.96 ft | 14Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.02 ft | +1.40 ft | 14Severe | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 8.00 ft | +1.10 ft | 14Severe | Ryan Avenue, Plymouth Avenue, Park Terrace |
Latest verified
Most recent days
| Date | High water · San Francisco | vs tide tables | Roads at risk | Deepest streets (model) |
|---|---|---|---|---|
| 7.19 ft | +0.86 ft | 9Likely | Ryan Avenue, Plymouth Avenue, Park Terrace | |
| 7.11 ft | +0.80 ft | 1Likely | Sycamore Avenue | |
| 6.77 ft | +0.59 ft | 1Possible | Sycamore Avenue | |
| 6.63 ft | +0.67 ft | 1Possible | Sycamore Avenue | |
| 6.65 ft | +0.76 ft | 1Possible | Sycamore Avenue |
Every day, every year
Browse by year
About this data: method, sources and free downloads
Since 1996, NOAA's San Francisco tide gauge has recorded water high enough for FloodRoute's model to put at least one Mill Valley road at risk on 1,517 days, about 50 a year. The highest water was 8.38 ft on Friday, February 6, 1998, 2.21 ft above the tide tables; at that level the model estimates 23 Mill Valley roads were at risk, including Ryan Avenue, Plymouth Avenue and Park Terrace. Those days have become more common: about 40 a year in 1996–2005, versus 61 a year in 2016–2025.
For every day since 1996 we take NOAA's verified highest observed water at the tide gauge, adjust it to the town's prediction station exactly as the live forecast does (the gauge's departure from the tide tables, minus the departure already built into our calibration), and run FloodRoute's flood model on today's road network and street elevations. A day counts when at least one road in the town is at or below that water level by the model's rules. Rain is not included, so wet days were likely worse.
Gauge: NOAA 9414290 (San Francisco) · tide tables: NOAA 9414806 (Sausalito). Heights are feet above MLLW.
Free to use under the Open Database License (ODbL) 1.0. Credit: FloodRoute (floodroute.com), © OpenStreetMap contributors, NOAA CO-OPS. Please describe it as estimates, never as observed flooding.
Cite as: FloodRoute (2026). Mill Valley, CA king tide flood history (model estimates). https://floodroute.com/ca/mill-valley/history. Open Database License (ODbL) 1.0.
FAQ
Mill Valley flood history: questions, answered
How often do roads flood at high tide in Mill Valley?
By FloodRoute's estimate, at least one Mill Valley road was at risk on 1,517 days between 1996 and Sep 30, 2026, about 50 a year. Those days have become more common: about 40 a year in 1996–2005, versus 61 a year in 2016–2025. Most of those days are shallow water on a few low streets; the biggest days put dozens of roads at risk.
What was the highest tide in Mill Valley since 1996?
Friday, February 6, 1998: NOAA's San Francisco tide gauge recorded 8.38 ft (MLLW), 2.21 ft above the tide tables. At that level FloodRoute's model estimates 23 Mill Valley roads were at risk, including Ryan Avenue, Plymouth Avenue and Park Terrace.
When did a high tide last put Mill Valley roads at risk?
The most recent day in the verified record is Wednesday, September 30, 2026: 7.19 ft at the San Francisco gauge, 9 roads at risk. NOAA verifies data with a lag of a month or two; the live forecast covers today and the weeks ahead.
Is this a record of actual flooding in Mill Valley?
No. Estimates, not records of actual flooding. Each day is NOAA's verified high water at the tide gauge, run through FloodRoute's flood model on today's roads and elevations, in dry weather. Drains, levees, tide gates, rain, road changes and elevation error all mean real conditions differed. Not for property, real-estate, insurance, lending, engineering or legal decisions. Neighbor flood reports in the FloodRoute app are the ground truth we use to check and improve the model.
Can I use this data?
Yes. Download it as CSV or JSON under the Open Database License (ODbL) 1.0, with attribution to FloodRoute (floodroute.com), © OpenStreetMap contributors, NOAA CO-OPS. Please describe it as estimates, never as observed flooding. More on the open data page.
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