⟁ California Well Data field records · 2026 survey

California Well Data › Sonoma County

Sonoma County, California: well depth, water level & drilling cost

✓ 37,891 DWR records · verified 2026-08-14

195 ftmedian well depth
100 ft–295 fttypical depth range
40 ftmedian static water level
25 gpmmedian yield (19,527 tests)

How deep are wells in Sonoma County, California?

The median drilled well depth in Sonoma County is 195 ft, based on 29,069 wells with recorded depths in the state DWR database. Half of all wells fall between 100 ft and 295 ft; 90% are shallower than 420 ft. Wells drilled since 2016 have a median depth of 290 ft.

How much does it cost to drill a well in Sonoma County?

Applying published per-foot rates to the local median depth of 290 ft: drilling and casing alone typically runs $7,250–$18,850; a complete system including pump, pressure tank, and hookup typically runs $17,400–$29,000. Actual quotes depend on site access, geology, and casing requirements.

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What is the static water level in Sonoma County?

The median static water level is 40 ft below ground surface (middle half of wells: 20 ft–72 ft), from 17,880 measurements.

How much water do wells in Sonoma County produce?

The median tested yield is 25 gpm (middle half: 15 gpm–50 gpm), from 19,527 pump tests. A typical household needs 5–10 gpm.

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Drilled depth distribution

0–50 ft 2,294 50–100 ft 4,587 100–150 ft 4,147 150–200 ft 3,757 200–300 ft 7,211 300–400 ft 3,450 400–600 ft 2,553 600+ ft 1,070

Who drills wells in Sonoma County?

Companies by number of wells completed in this county since 2016, per filed well completion reports (California Department of Water Resources).

DrillerWells since 2016
WEEKS DRILLING AND PUMP CO896
FISCH BROS DRILLING725
LES PETERSEN DRILLING & PUMP INC324
IRWIN WELL DRILLING304
MICKELSON ENTERPRISES INC134
CLEAR HEART DRILLING INC127
CASCADE DRILLING L P83
NUTTING AND JENSEN DRILLING37

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Method: medians computed from DWR records (filed well completion reports, water-supply uses only (destruction, repair and monitoring wells excluded); depths 0–5,000 ft). Cost estimate applies published per-foot ranges (checked 2026-06-11) to the local median depth — full methodology & sources.