Well water testing is how you find out whether the water coming out of your tap is actually safe to drink, and it matters whether you own a well near Gresham, are buying a home on one, or just noticed a change in taste or smell. This guide explains what a professional test checks for, how a lab analysis compares to a store-bought well water testing kit, and what Oregon requires when a well changes hands in a real estate sale. You will also learn how often to test, what results like coliform or nitrate actually mean, and what to do next if something comes back high. Everything here comes from a working well contractor in the east Portland metro, not a lab that mails you a report and disappears.

What You'll Find in This Guide

What a Well Water Test Actually Checks For

A well water test is a menu of individual analyses, and the right combination depends on why you are testing. Most homeowners around Gresham, Sandy, Boring, and Damascus start with the core panel: total coliform bacteria, E. coli, nitrate, and arsenic. These four cover the most common health risks in private wells on the Clackamas and Multnomah County rural edge.

Total coliform bacteria usually means surface water or soil is entering your well, often through a cracked cap, bad seal, or compromised casing. E. coli is more serious—it signals contamination from human or animal waste. Neither has a taste or smell, so testing is essential for detection.

Nitrate matters most for households with infants or pregnant individuals. It typically comes from fertilizer, septic systems, or livestock, and levels shift seasonally. Arsenic occurs naturally in Oregon's geology, so a well can pull it from rock with no contamination event. Beyond these four, labs can test for lead, iron, manganese, hardness, pH, and other parameters when needed.

According to the EPA, over 23 million U.S. households rely on private wells for drinking water. A USGS study of 2,100 private wells found about one in five contained at least one contaminant above health benchmarks. A clean-looking glass of water tells you almost nothing.

Lab reports use terms like MCL, mg/L, and "absent/present." Our plain-English well water testing glossary defines the vocabulary so you can read your report without guessing.

DIY Well Water Testing Kit: When to Use One

A well water testing kit from the hardware store or Amazon has a real place in well ownership. However, it is not a substitute for a certified lab analysis, and knowing the difference saves you from two expensive mistakes: trusting a bad result, or paying for lab work you did not need.

What a DIY Kit Does Well

A basic well water testing kit works fine as a screening tool. For example, test strips can flag obvious problems with pH, hardness, iron, or high nitrate in a few minutes at your kitchen sink. If you notice a sudden change in taste, color, or smell, a quick strip test can tell you whether something shifted and whether it is worth a lab sample. Additionally, kits are cheap, so testing monthly between annual lab tests costs almost nothing.

Where DIY Kits Fall Short

The limits show up exactly where the stakes are highest. Bacteria results from a home well water testing kit are unreliable because the sample sits at room temperature instead of being cultured under lab conditions. Arsenic and lead need instrument-level detection at parts-per-billion sensitivity, which no strip can deliver. Beyond that, no lender, county, or buyer will accept a DIY result for a real estate transaction. Oregon requires certified lab results for that, full stop.

In practice, the smart pattern looks like this. Use a certified lab test once a year for bacteria and nitrate, and after any repair, flooding event, or change in water quality. Then use an inexpensive well water testing kit between lab tests as an early-warning system. If a strip flags something, confirm it with the lab before you spend money on treatment. This two-layer approach costs less than reacting to problems after someone gets sick, and it keeps you from installing a filtration system based on a strip that misread your iron level.

If you are weighing kit prices against lab panels, our guide to well water testing costs compares the real numbers side by side, including what drives a quote up or down.

Testing for a Home Sale: What Oregon Requires

Real estate transactions are where well water testing stops being optional. Oregon law requires the seller of a property with a domestic well to test the water for total coliform bacteria, nitrate, and arsenic when the property sells, and to submit those results to the state. The Oregon Health Authority's Domestic Well Safety Program publishes the details, and buyers and lenders increasingly check that the paperwork exists.

This catches a lot of sellers off guard. Many wells in Corbett, Estacada, and Oregon City have never been tested since the day they were drilled. As a result, the sale test is often the first hard look at the water in decades, and surprises happen. A coliform hit or an elevated arsenic result in the middle of a pending sale creates pressure fast, because now there is a deadline, a nervous buyer, and a lender asking questions.

Here is the part most people miss: a failed test is rarely a dealbreaker. Coliform bacteria often traces back to a fixable well problem, like a damaged cap or a seal that needs replacement, followed by shock chlorination and a retest. Arsenic and nitrate usually resolve with a point-of-use or whole-house treatment system. The difference between panic and a smooth closing is working with someone who can diagnose the cause and fix it, not just hand you a lab report and wish you luck.

How Often to Test Outside a Transaction

Even without a sale on the calendar, test annually for bacteria and nitrate at minimum. Additionally, test any time you repair the well or pump, after nearby flooding, if a neighbor finds a problem, or when someone in the house is pregnant or an infant arrives. Oregon takes its groundwater seriously at the state level too. The Oregon Water Resources Department maintains more than 400 state observation wells and measures over 1,200 additional wells to track aquifer conditions across the state. Your private well gets no such monitoring, so the annual test is on you.

Pairing the water test with a broader well inspection often makes sense at sale time. According to Angi, a typical professional well inspection runs $250 to $550, and it covers the pump, pressure tank, and wellhead alongside the water itself.

Reading Your Results and Deciding What to Do Next

The test is the easy part; the harder question is what to do with results. Start by sorting them into three buckets. First, health-based results: bacteria, nitrate, arsenic, and lead have enforceable benchmarks, and anything above them needs action. Second, aesthetic results: iron, manganese, hardness, and pH affect taste, staining, and plumbing life but won't make you sick. Fix them on your own timeline and budget. Third, informational results like turbidity or conductivity help a professional diagnose what is happening downhole.

Next, match the result to its likely cause before buying anything. A positive coliform test with clean E. coli often points to a wellhead problem, not the aquifer. The fix might be a new cap, sanitizing chlorination, and a retest—not a permanent disinfection system. Repeated bacteria hits after chlorination suggest a deeper structural issue with the casing or seal, requiring a well repair conversation. High iron might call for filtration or signal a corroding component in an aging well.

This is why "who runs the test" matters as much as the test itself. A lab gives numbers. A driller who tests water connects those numbers to the physical well: its depth, construction, age, and what typically fails in wells in your area. The goal isn't a report for your filing cabinet—it's safe water, and sometimes the path runs through the well itself rather than a treatment system.

Don't let a confusing result sit unread. Look up unfamiliar terms, compare your numbers to benchmarks, and get a second opinion on any quote pushing expensive equipment.

Ready to Get Started?

If your well is due for a test, your water has changed, or a home sale just put a deadline on the question, we can help. We test well water across Gresham, Sandy, Boring, Damascus, Estacada, Corbett, and Oregon City, and because we drill and repair wells for a living, we can act on whatever the results show. Call us and get a straight answer about your water, your well, and what it will cost to fix anything the test turns up.