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 2026-10-13); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
71
Moderate
Drought index
0
None
Area in D2+
0%
0% exceptional (D4)
Gauges below normal
36%
of 22 reporting
Median flow
115%
p50 of record
Water assets
856
6 springs · 743 wells
USGS gauges (28)
- ALAMEDA C NR FREMONT CA111791000 cfsp1 · much below normal
- ALAMEDA C NR NILES CA111790008 cfsp9 · much below normal
- INDIAN C NR SUNOL CA111738000 cfsp10 · 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
- CASTRO VALLEY C A HAYWARD CA111810080 cfsp18 · below normal
- ARROYO DE LA LAGUNA A VERONA CA111769006 cfsp24 · below normal
- SAN LORENZO C A SAN LORENZO CA111810401 cfsp42 · normal
- SAN LORENZO C AB DON CASTRO RES NR CASTRO V CA111808250 cfsp47 · normal
- ARROYO HONDO NR SAN JOSE CA111732001 cfsp49 · normal
- ALAMEDA C FLOOD CHANNEL A UNION CITY CA111807000 cfsp52 · normal
- CROW C NR HAYWARD CA111809000 cfsp54 · normal
- SAN LORENZO C A HAYWARD CA111810001 cfsp56 · normal
- ALAMEDA C BL DIV DAM NR SUNOL CA111729550 cfsp66 · normal
- ARROYO VALLE NR LIVERMORE CA111765008 cfsp69 · normal
- ALAMEDA C BL WELCH C NR SUNOL CA111735757 cfsp75 · normal
- CALAVERAS C NR SUNOL CA111735008 cfsp75 · normal
- SAN MATEO C BL LO CRYSTAL SP RES NR SAN MATEO CA111627534 cfsp76 · above normal
- ALAMEDA C AB DIV DAM NR SUNOL CA111729450 cfsp76 · above normal
- ALAMEDA C BL CALAVERAS C NR SUNOL CA111735108 cfsp78 · above normal
- ALAMO CN NR PLEASANTON CA111746004 cfsp78 · 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
- ALAMEDA C A SUNOL WATER TEMPLE A SUNOL CA1117416015 cfsno long-term record
- ARROYO DE LA LAGUNA A CORTE MADRID NR PLEASANTON111763406 cfsno long-term record
- ARROYO VALLE BL LANG CYN NR LIVERMORE CA11176400no readingno long-term record
- SAN ANTONIO C A INDIAN CREEK ROAD NR SUNOL CA3735071214721010 cfsno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-10-19 | 0 | 0 | 8/22 | p50 |
| 2026-10-18 | 0 | 0 | 6/22 | p47 |
| 2026-10-17 | 0 | 0 | 6/22 | p53 |
| 2026-10-16 | 0 | 0 | 5/22 | p51 |
| 2026-10-15 | 0 | 0 | 6/22 | p53 |
| 2026-10-14 | 0 | 0 | 5/22 | p58 |
| 2026-10-13 | 0 | 0 | 6/22 | p54 |
| 2026-10-12 | 0 | 0 | 6/22 | p53 |
| 2026-10-11 | 0 | 0 | 6/22 | p55 |
| 2026-10-10 | 0 | 0 | 4/22 | p55 |
| 2026-10-09 | 0 | 0 | 4/22 | p54 |
| 2026-10-08 | 0 | 0 | 5/22 | p57 |
| 2026-10-07 | 0 | 0 | 5/22 | p55 |
| 2026-10-06 | 0 | 0 | 5/22 | 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