St. Johns River at Mayport (in MHHW)
Florida — Water Level & Flood Stage
Located in Duval County, Florida on the St. Johns River. Live water level data from USGS, updated every 15 minutes.
Current Water Level
Gage Height
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Streamflow
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Last Reading
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This is an NWS forecast point (LID: MYPF1). Live data may be limited. View on NWS AHPS →
Flood Stages
Major Flood
3.3 ft
Moderate Flood
2.3 ft
Minor Flood
1.8 ft
Action Stage
1.3 ft
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
What Floods at Each Level
3.3 ft
Major Flooding - 3.3 feet above MHHW - Major Coastal Flooding. Coastal Flood Warning needed. Extensive inundation of structures and roads in the area is expected. Evacuations of people or transfer of property to higher ground is likely and the advice of Emergency Management should be heeded. Extensive beach erosion is possible and possible breaches of the dune line...especially in lower areas and beach access areas. Significant past events: 2 October 1898 Hurricane.
2.29 ft
Moderate Flooding - 2.3 feet above MHHW - Significant Coastal Flooding begins and Coastal Flood Warning needed. Some flooding of structures and roads along the coast, St Johns River and other inland waterways is expected. Evacuation of people or property to higher ground is possible and the advice of Emergency Management or local officials should be heeded. Significant past events: Hurricane Dora 1964.
1.8 ft
Minor Flooding - 1.8 feet above MHHW - Coastal Flood Advisory is likely and Coastal Flood Warning Possible if significant wind and wave action drives water levels higher along the immediate coast. Flooding of low lying roads and campgrounds possible. Water levels may surge up the dune lines and into beach access areas. Some boat ramps and docks near the St. Johns River entrance and other inland waterways may begin to flood. Significant past events: Tropical Storm Fay...Hurricane Jeanne and 11/23/1984.
1.3 ft
Action Stage - 1.3 feet above MHHW - Coastal Flood Advisory is possible if significant wind and wave action drives water levels higher along the immediate coast. Should water levels continue rising...preparations to protect property should begin.
Impact statements from the National Weather Service, describing what typically happens at each water level.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Oct 1, 1898 | 6.5 ft | — |
| Oct 1, 1898 | 6.5 ft | — |
| Nov 10, 2022 | 3.41 ft | — |
| Nov 10, 2022 | 3.41 ft | — |
| Oct 7, 2016 | 3.21 ft | — |
About This Gauge
NWS LID
MYPF1
River
St. Johns River
County
Duval, FL
Coordinates
30.3917°N, 81.4300°W
Get Flood Alerts for St. Johns River
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of St. Johns River at Mayport (in MHHW)?
The St. Johns River at Mayport (in MHHW) gauge is maintained by USGS and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for St. Johns River at Mayport (in MHHW)?
The NWS-defined flood stage for St. Johns River at Mayport (in MHHW) is 1.8 feet. Action stage begins at 1.3 feet. Moderate flooding starts at 2.3 feet, and major flooding at 3.3 feet.
How do I get alerts when St. Johns River rises?
Download StormCast free on Google Play, go to River Gauges, and add St. Johns River at Mayport (in MHHW) to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category — even when your screen is off.
Where is the St. Johns River at Mayport (in MHHW) gauge located?
The gauge is located in Duval County, Florida at coordinates 30.3917°N, 81.4300°W. Data is provided by the U.S. Geological Survey and the National Weather Service.
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Source & Notes
Data provided by: National Ocean Service
- Water levels are referenced to the Mean Higher High Water (MHHW) Datum. This datum can be used to approximate sea water inundation of normally dry ground near the coast. For specific impacts, please refer to the statements on this page.