Buying a home with a well in Washington: what to check

When you buy a house on a well, you are also buying its water supply, and nobody else maintains it. Washington DOH says it doesn’t oversee or approve water sources for individual homes; that is left to local government, and after the sale it is up to you. A well problem found before closing is a negotiating point. Found after, it’s your bill. Here’s what to check.

1. Find the well log

Every well drilled in Washington should have a well report (well log) on file with Ecology. Drillers must file one within 30 days of completing a well (WAC 173-160-141). It records the well’s depth, casing, seal, the formations and water-bearing zones, static water level and the yield test at the time of drilling, and the Ecology well tag number.

• Search Ecology’s records. Use the well report search tools. Ecology’s tips: search by map or text, use partial address information, and if one search fails, try another. Locations are only accurate to the township, section and range, so compare the log’s details (depth, date, tag number) with the well itself.
• Ask the seller. Ecology’s guide tells owners to keep a copy of the well report and a bill of materials, and NGWA suggests keeping the well record with the house deed so it passes to future owners.
• No log? Older wells may not have one, and Ecology warns that reports are historical documents that can be incomplete or inaccurate. Some counties then require a test in its place. Yakima County, for example, requires a 4-hour drawdown test and a record of the well depth when connecting to an existing well with no report.

Compare the log with what you see. The casing should stand at least 6 inches above ground with a secured cap, and pit wells are prohibited (WAC 173-160-291). The well must be at least 100 feet from the edge of a drainfield and 50 feet from a septic tank (WAC 173-160-171).

2. Ask for a flow or yield test

A well log shows what the well produced when it was drilled, possibly decades ago. A current flow test tells you what it delivers now. There is no single statewide standard for a home-sale flow test; the requirements come from the county, the lender and your purchase contract.

Examples of county rules:

These are building and connection rules, not sale rules, but they show what local health officials consider adequate. DOH’s guidance to local governments recommends planning for at least 350 gallons per day per home at maximum daily demand and 200 gallons per day on average. NGWA says most homes need a well that can produce 7 gallons per minute, or storage holding at least a day’s supply.

Ask the tester to report the flow rate, how long the test ran, the water level before, during and after pumping, and whether the well recovered. A flow test on a dry late-summer day tells you more than one after a wet spring.

3. Test the water

DOH says the county health or planning department, or the lender, “may require the seller to provide water-sampling results” when a home with a private well is sold, and Ecology says that is the case in most counties. Even when nobody requires it, test.

• Coliform bacteria and nitrate. DOH recommends these every year for every private well. Ecology says both can affect health rapidly, possibly after a single drink.
• Nitrate above 10 mg/L. DOH says not to drink it if you’re pregnant or trying to become pregnant, and not to give it to babies under 12 months.
• Arsenic. DOH says arsenic is found in well water throughout Washington, and recommends no more than 10 ppb for drinking and cooking.
• Local concerns. DOH’s guidance adds iron and manganese, chloride near salt water and uranium in northeast Washington.
• PFAS. Ecology recommends testing for PFAS if the well hasn’t been sampled for it, and names areas where it knows groundwater is contaminated. See testing your well water.

Use an Ecology-accredited lab (testing directory), and have the sample taken by someone other than the seller if you can (see water sampling). A bacteria sample taken right after the well was chlorinated can hide a problem; ask whether the well was recently disinfected.

Seller disclosure. Ecology’s PFAS guide explains that Washington’s seller disclosure form (Form 17, under chapter 64.06 RCW) asks about water treatment systems and groundwater contamination. A seller who has had the well tested and found PFAS must give those results to buyers.

4. Shared wells and Group B systems

Many Washington homes share a well with neighbors. The number of homes changes the rules:

• One or two connections. The state’s Group B rule doesn’t apply unless the local board of health has adopted rules for them, or DOH decides it’s needed (WAC 246-291-005). The well is usually a private matter between the owners.
• Fewer than 15 connections and fewer than 25 people a day is a Group B public water system, regulated under chapter 246-291 WAC.
• 15 or more connections, or 25 or more people: Ecology’s guide says the Department of Health must approve the well location before it is built.

For any shared well, ask for the written agreement among the owners. Check that it covers who pays for repairs, power and testing, access to the wellhead, and what happens if one owner wants to leave. Ask whether the system is registered with DOH or the county, and for its recent test results.

5. The water right and permit-exempt status

Most single-family wells use the groundwater permit exemption in RCW 90.44.050: domestic use up to 5,000 gallons a day, plus watering up to half an acre of lawn or noncommercial garden. Ecology says each project gets one exemption of each type, however many wells it has, so homes on a shared well share one limit. Exempt use still sets a priority date, from when the water was first put to use, and Ecology can regulate it if it interferes with senior rights.

Newer homes may carry tighter limits. Wells approved under the Streamflow Restoration Act (chapter 90.94 RCW) in certain watersheds are limited to 3,000 or 950 gallons a day per connection, and those restrictions must be recorded on the property title. Check the title report for them. If you plan to irrigate more than half an acre or add a second home, talk to Ecology or a water rights consultant before you buy.

6. Old wells that need decommissioning

Older properties often have a disused hand-dug well, an old drilled well replaced by a newer one, or a well hidden under a deck or in a shed. Under WAC 173-160-381, a well that is unusable, abandoned or permanently out of use, or that poses a safety or health hazard, must be decommissioned. Ecology’s guide says that is the property owner’s responsibility, which means it becomes yours at closing.

Decommissioning means cleaning out the well and sealing it with approved materials, and it needs a notice of intent with a $50 fee (WAC 173-160-151). Ask the seller about every well on the property, and ask your inspector to look for signs of others. Price the work with a decommissioning contractor before closing.

7. What a well inspection should include

A home inspector’s general inspection may only glance at the well. Ask for a dedicated well inspection from a well inspection provider. NGWA’s annual checkup is a good template. It calls for a licensed or certified water well professional to check:

• the system’s water output (flow);
• the water level before and during pumping, if possible;
• the pump motor’s amp load, grounding and line voltage;
• the pressure tank and the pressure switch contacts;
• that the equipment is sanitary and meets local code;
• coliform bacteria, nitrate and other local contaminants;
• and to deliver a written report with all lab and test results.

Add to that list:

• the casing height, cap and setbacks;
• the well log, and whether it matches the well;
• any treatment equipment;
• any other wells on the property.

NGWA’s warning signs to look for include pressure drops or surges, frequent pump cycling, reduced flow, cloudy or foul-smelling water, damaged casing or a deteriorated cap, and signs of flooding. If any of these turn up, see pump repair and replacement quotes.

Questions for the seller

1. Do you have the well log, and does the well have an Ecology tag?
2. When was the well drilled, and by whom? Has it been deepened, repaired or hydrofractured?
3. When were the pump and pressure tank last replaced? Do you have the invoices?
4. Have you ever run short of water, especially in late summer?
5. Do you have water test results? When were coliform, nitrate and arsenic last tested? Ever for PFAS?
6. Is there any treatment equipment? Is it owned or leased, and what does it treat?
7. Is the well shared? Is there a written agreement, and how are costs split?
8. Are there any other wells on the property, in use or not?
9. Are there any water-use restrictions recorded on the title?
10. Where is the septic tank and drainfield in relation to the well?

Red flags

• No well log, and no willingness to allow a flow test.
• A water test taken by the seller, from an unknown lab, or right after the well was chlorinated.
• A well in a pit, a casing at or below ground level, or a loose or missing cap.
• A drainfield closer than 100 feet to the well.
• A shared well with no written agreement.
• Signs of an old well with no record of decommissioning.
• A treatment system nobody can explain, especially one for arsenic, nitrate or PFAS.