When people hear that a well “failed” a water test, they often jump straight to the fear of drilling a new well. In reality, that outcome is rare. Most problems fall into predictable categories, and most are solved for hundreds—not tens of thousands—of dollars.
Scenario 1: Coliform bacteria detected (most common)
This is the least expensive and most frequent issue.
Typical cause
Temporary surface contamination, heavy rain, minor wellhead issues, or long periods of non-use.
This is the scenario well professionals see most often. A positive coliform test usually means surface water or shallow groundwater has found a way into the well. It does not automatically mean sewage or dangerous pathogens are present, but it does mean the well’s protective barrier has been compromised.
In many cases, the fix is straightforward. The well and household plumbing are disinfected through shock chlorination, the wellhead is inspected, and any obvious issues—like a cracked cap, missing sanitary seal, or poor grading around the casing—are corrected. Afterward, the water is retested to confirm the bacteria are gone.
All well water systems require a varying degree of Operations & Maintenance (O&M) services. Some wells only need to be periodically tested, have the tanks & electrical components checked, tuned up, and replaced as necessary. Some wells require periodic cleaning, brushing, and air jetting to maintain peak production. Some filter systems require only the addition of salt in the brine tank or UV bulbs in the purification process on an annual basis, while others require weekly to monthly testing, filtration adjustment, and chemical additions.
When it gets more expensive
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If bacteria returns repeatedly
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If the casing or seal is compromised
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If the well is in a pit or low area that collects runoff
When bacteria keeps coming back
Repeated positive coliform tests usually point to a structural or environmental problem rather than a temporary contamination event. This might involve a deteriorating casing, a failed seal below ground, or a well that draws from a shallow, easily influenced water source. Older wells are particularly susceptible.
At this stage, fixing the problem often means more than disinfection. A contractor may need to inspect the well using a camera, reseal or extend the casing, improve drainage around the well, or install a permanent disinfection system such as ultraviolet treatment.
Costs rise accordingly. Most homeowners spend $1,500 to $5,000 to permanently resolve chronic bacterial contamination. While that number can feel uncomfortable, it’s still far less than replacing the well—and it usually eliminates the problem for good.
Nitrates above safe limits
Nitrates are different because the issue usually isn’t the well structure itself. Elevated nitrates typically come from surrounding land use, such as septic systems or agriculture, and they are invisible and unaffected by boiling or chlorination.
Because of that, treatment focuses on the water people consume rather than the entire system. Many households install a reverse-osmosis unit at the kitchen sink to provide safe drinking and cooking water. This approach is effective and relatively affordable.
Most families spend $500 to $1,400 for installation and initial setup, with modest annual maintenance costs. Whole-house nitrate treatment is possible but far more expensive and rarely necessary for typical residential use.
Arsenic detection
Arsenic often surprises homeowners because it is naturally occurring and unrelated to pollution. In certain parts of Washington, arsenic shows up consistently due to local geology, and fixing the well itself does not make it go away.
Treatment is the standard solution. Depending on household needs, this may involve an under-sink system or a whole-house treatment unit designed specifically for arsenic removal.
Costs generally range from $1,000 to $6,000, depending on system type and scale. Ongoing maintenance is required, but once properly installed, arsenic treatment is highly reliable.
The pattern most homeowners don’t see until it’s too late
If your home uses a private well (not connected to a public water system), you are fully responsible for testing and maintaining your water supply. Unlike city water, private well water is not regulated or monitored by government agencies once installed — meaning safe water is up to you. Problems caught early tend to cost a few hundred dollars. Problems addressed after multiple warnings often cost a few thousand. Problems ignored for years can become five-figure projects.
A “bad” test result is usually not a disaster—it’s a signal. Responding early almost always keeps costs manageable and the well usable. When a well test fails, lenders and inspectors are not asking whether the water is perfect forever. They are asking whether the risk has been identified, mitigated, and stabilized in a way that protects the borrower, the collateral, and future occupants.
A solution is considered “permanent” when it breaks the contamination pathway or controls it continuously, and when that fix can be documented and verified. Inspectors and lenders rarely require a new well unless one or more of the following is true: the well cannot be sealed or repaired, contamination is severe and untreatable at reasonable cost, or the well does not meet minimum construction standards and poses ongoing risk.
In these cases, drilling a new well is viewed as eliminating uncertainty entirely. That’s why it’s considered the gold standard—but also why it’s treated as a last resort.
If you need well repairs, a well inspection, a well drilled, or any of the other well and water system related services we provide, you can email us 24 hours a day at service@jkawelldrilling.com, or call us at (360) 684-1932 (office hours are Monday-Friday, 730AM – 300PM).
