Washington Well Data field records · 2026 survey

Washington Well Data › King County

King County, Washington: well depth, water level & drilling cost

✓ 4,737 Ecology records · verified 2026-07-28

142 ftmedian well depth
88 ft–238 fttypical depth range
76 ftmedian static water level
20 gpmmedian yield (931 tests)

How deep are wells in King County, Washington?

The median drilled well depth in King County is 142 ft, based on 4,686 wells with recorded depths in the state Ecology database. Half of all wells fall between 88 ft and 238 ft; 90% are shallower than 344 ft. Wells drilled since 2016 have a median depth of 157 ft.

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

Applying published per-foot rates to the local median depth of 157 ft: drilling and casing alone typically runs $3,925–$10,205; a complete system including pump, pressure tank, and hookup typically runs $9,420–$15,700. Actual quotes depend on site access, geology, and casing requirements.

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What is the static water level in King County?

The median static water level is 76 ft below ground surface (middle half of wells: 30 ft–141 ft), from 837 measurements.

How much water do wells in King County produce?

The median tested yield is 20 gpm (middle half: 10 gpm–35 gpm), from 931 pump tests. A typical household needs 5–10 gpm.

Pull every recorded well near a King County address — $19

Bad well water in King County?

Iron staining, rotten-egg smell, hard water, or a failed test at closing — Salish Water Works, a new Puget Sound company, publishes its treatment systems and planned prices up front and specs the fix from your water test. No in-home sales visit. Installation opens Fall 2026; the waitlist is open now and waitlist members get first slot priority.

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Drilled depth distribution

0–50 ft 440 50–100 ft 1,007 100–150 ft 1,007 150–200 ft 688 200–300 ft 794 300–400 ft 458 400–600 ft 235 600+ ft 57

Who drills wells in King County?

Licensed drillers by number of wells completed in this county since 2016, per filed well reports (license roster: Washington Department of Ecology).

DrillerWells since 2016
Pierce Kiltoff134
Rodney Gilseth JR117
Mark Wiese114
Chris Gregory71
Michael Cyrier69
Justin Bevins53
Aaron Ocheltree49
Gerald Gibson37

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Looking at a specific property in King County?

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Well records by ZIP code in King County

Median depth, water level, and yield for each ZIP code with recorded wells.

Method: medians computed from Ecology records (water wells only — soil/environmental borings and decommissions 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.