San Francisco Bay HUC8 18050004
A 3,453 km² sub-basin of the California region in CA. Drought coverage is from the US Drought Monitor (map of 2026-09-01); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
73
Moderate
Drought index
0
None
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
30%
of 20 reporting
Median flow
131%
p54 of record
Water assets
856
6 springs · 743 wells
USGS gauges (28)
- ALAMEDA C NR NILES CA111790006 cfsp9 · much below normal
- SAN ANTONIO C NR SUNOL CA111740000 cfsp10 · below normal
- DRY C A UNION CITY CA111805000 cfsp10 · below normal
- CULL C AB CULL C RES NR CASTRO VALLEY CA111809600 cfsp10 · below normal
- CROW C NR HAYWARD CA111809000 cfsp18 · below normal
- ARROYO DE LA LAGUNA A VERONA CA111769006 cfsp24 · below normal
- CASTRO VALLEY C A HAYWARD CA111810080 cfsp31 · normal
- ALAMEDA C NR FREMONT CA111791002 cfsp32 · normal
- ARROYO HONDO NR SAN JOSE CA111732001 cfsp42 · normal
- SAN LORENZO C AB DON CASTRO RES NR CASTRO V CA111808250 cfsp50 · normal
- SAN MATEO C BL LO CRYSTAL SP RES NR SAN MATEO CA111627533 cfsp58 · normal
- ALAMEDA C FLOOD CHANNEL A UNION CITY CA111807000 cfsp58 · normal
- ALAMEDA C BL DIV DAM NR SUNOL CA111729550 cfsp59 · normal
- SAN LORENZO C A HAYWARD CA111810000 cfsp60 · normal
- CALAVERAS C NR SUNOL CA111735007 cfsp65 · normal
- ARROYO VALLE NR LIVERMORE CA111765009 cfsp69 · normal
- ALAMEDA C BL WELCH C NR SUNOL CA111735756 cfsp73 · normal
- ALAMO CN NR PLEASANTON CA111746003 cfsp78 · above normal
- ALAMEDA C AB DIV DAM NR SUNOL CA111729450 cfsp80 · above normal
- ALAMEDA C BL CALAVERAS C NR SUNOL CA111735108 cfsp83 · above normal
- SAN MATEO C AB JUNCTION BOX A DAM1 NR HILLSBOROUGH111627350 cfsno long-term record
- SAN MATEO C BL JUNCTION BOX A DAM1 NR HILLSBOROUGH111627370 cfsno long-term record
- INDIAN C NR SUNOL CA11173800no readingno long-term record
- ALAMEDA C A SUNOL WATER TEMPLE A SUNOL CA111741600 cfsno long-term record
- ARROYO DE LA LAGUNA A CORTE MADRID NR PLEASANTON111763404 cfsno long-term record
- ARROYO VALLE BL LANG CYN NR LIVERMORE CA11176400no readingno long-term record
- SAN LORENZO C A SAN LORENZO CA11181040no readingno long-term record
- SAN ANTONIO C A INDIAN CREEK ROAD NR SUNOL CA373507121472101no readingno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 0 | 0 | 6/20 | p54 |
Top water assets
- 67Del Vallereservoir
- 66Bear Gulchreservoir
- 65San Mateo C Bl Lo Crystal Sp Res Nr San Mateo Cariver
- 65Arroyo Valle Bl Lang Cyn Nr Livermore Cariver
- 65Alameda C Bl Calaveras C Nr Sunol Cariver
- 65Calaveras C Nr Sunol Cariver
- 65Alameda C Bl Div Dam Nr Sunol Cariver
- 65Arroyo Hondo Nr San Jose Cariver
- 65San Lorenzo C A Hayward Cariver
- 65Alameda C Flood Channel A Union City Cariver