Oregon county well guide

Well Water in Yamhill County, OR: Testing, Contractors and Rules

About 7,872 households in Yamhill County, 19% of the county, rely on a private well. Nobody tests that water unless the owner does.

Labs within 40 milesLicensed contractors
19%of households on a private well
Share on wells, county vs state
Yamhill County19%
Oregon average16%
25licensed contractors serve the county
21 mito the nearest certified lab, Waterlab Corp.
Yesstatewide test required when a home is sold

Yamhill County has an estimated 7,872 households on private wells, 19% of the county. If you are one of them, testing, treatment and repairs are yours to arrange.

Local rules for wells in Yamhill County

Private wells in Yamhill County follow Oregon's statewide rules, administered by Oregon Water Resources Department, Well Construction and Compliance Section. No water test is required by the state when a new well is completed. A test is also required when a home with a well is sold. The cards below show the details and the official sources.

At a glance

Water test for a new wellNot required statewide

No statewide water test on a new well. The well must be built by an OWRD-licensed, bonded water supply well constructor (or by the landowner under a Landowner's Water Well Permit) to the OAR 690-210 standards, with a start card filed and the fee paid before drilling, a metal well ID tag attached, and a well report filed with OWRD within 30 days. Setbacks are 50 ft from a septic tank and 100 ft from a drainfield. Some counties ask for a bacteria test before a building permit is finaled, and lenders usually do.

Water test when a home is soldRequired

Yes. Oregon's Domestic Well Testing Act (ORS 448.271, OAR 333-061-0305 to 0335) requires the seller of a property with a domestic well to have the water tested by an ORELAP-accredited lab for arsenic, nitrate and total coliform bacteria, give the results to the buyer and report them to the Oregon Health Authority within 90 days of the sale. It is one of only a handful of state laws in the country that test private wells at transfer.

What the state recommends

The Oregon Health Authority recommends testing a domestic well every year for coliform bacteria and nitrate, and every three to five years for arsenic (found across the Willamette Valley, the Tualatin basin, Lane County and Klamath and Lake counties), plus pH, hardness, iron, manganese, lead and copper once. Add uranium and radon in Lane County and the Cascade foothills, and test again after flooding, well work or a change in taste, color or smell. In the Southern Willamette Valley and Lower Umatilla Basin Groundwater Management Areas, nitrate is the test that matters most.

Free or low-cost testingAvailable

No statewide free program. The OSU Extension Well Water Program runs free nitrate screening clinics around the state and publishes testing guidance, and Oregon Health Authority's Domestic Well Safety Program (971-673-0440) helps owners read results. The Lower Umatilla Basin (Morrow and Umatilla counties) has state-funded free nitrate testing and water delivery for affected wells. Otherwise the ORELAP labs below charge $30 to $60 for bacteria and nitrate and $150 to $250 for the real estate panel.

Getting your water tested near Yamhill County

6 certified labs within 40 miles serve Yamhill County, starting with Waterlab Corp. in Salem (about 21 miles from the county center). Each card below shows whether the lab takes homeowner samples and which tests it is certified for.

6 certified labs within 40 miles

Licensed well contractors serving Yamhill County

25 licensed contractors serve Yamhill County, including A J Gaunt and Son and All Seasons Well Drilling. Each profile carries the state license number and the date we checked it, and the filters below sort them by drilling, pump work or treatment.

Well depth and water chemistry

Wells in Yamhill County typically reach 130 to 300 feet; the median of 2,417 new domestic wells reported to OWRD since 2000 is 200 feet. What comes up with the water depends on the aquifer, and across Oregon the usual suspects are arsenic (naturally occurring across the willamette valley, the tualatin basin, lane county, the klamath and lake basins and parts of central oregon). A first full panel tells you which of them apply to your well.

Typical well depth

130 to 300 feet; the median of 2,417 new domestic wells reported to OWRD since 2000 is 200 feet

Contaminants to test for
  • Arsenic (naturally occurring across the Willamette Valley
  • The Tualatin basin
  • Lane County
  • The Klamath and Lake basins and parts of central Oregon)
  • Nitrate (Southern Willamette Valley
  • Lower Umatilla Basin and Northern Malheur groundwater management areas
  • And shallow wells in farm country)
  • Coliform bacteria (statewide
  • Worst in shallow and older wells)
  • Iron and manganese (valley alluvium and coastal sands)
  • Hardness (basalt and limestone areas)
  • Uranium and radon (Lane County granite and Cascade foothills)
  • Hydrogen sulfide (deep basalt wells)
  • Sodium and boron (some Willamette Valley aquifers)
  • PFAS near airfields and industrial sites

Neighboring counties: Marion County, Washington County, Polk County, Clackamas County.

What well work costs in Yamhill County

Basic bacteria and nitrate test$25 to $75lab fee, homeowner sample
Full panel lab test$150 to $400metals, VOCs, radiologicals
Well inspection$250 to $550flow, pressure, visual, water test
Submersible pump replacement$1,200 to $4,500parts and labor
Pressure tank replacement$400 to $1,200installed
Whole-house treatment system$800 to $6,000softener, iron filter, UV, RO
New well drilled$5,500 to $25,000about $25 to $65 per foot
Shock chlorination$80 to $300or about $20 as a DIY job

National ranges from published 2025 to 2026 contractor pricing. Local quotes vary with depth, access and materials.

Questions Yamhill County well owners ask

How many homes in Yamhill County are on a well?

About 7,872, or 19% of households, based on Census housing data and state well surveys. The share is highest outside the towns with public water.

Where is the closest certified lab to Yamhill County?

Waterlab Corp. in Salem, about 21 miles away. It accepts homeowner samples.

Do I need a permit to drill a well in Yamhill County?

No statewide water test on a new well. The well must be built by an OWRD-licensed, bonded water supply well constructor (or by the landowner under a Landowner's Water Well Permit) to the OAR 690-210 standards, with a start card filed and the fee paid before drilling, a metal well ID tag attached, and a well report filed with OWRD within 30 days. Setbacks are 50 ft from a septic tank and 100 ft from a drainfield. Some counties ask for a bacteria test before a building permit is finaled, and lenders usually do.

What does a well test cost near Yamhill County?

A bacteria and nitrate test runs $25 to $75 at most certified labs; a full panel with metals is $150 to $400. Mail-in kits cost about the same as walking in.