If you rely on a private well, you’re basically your own water utility. That can feel empowering (no monthly water bill surprises), but it also means the safety checks are on you. Unlike municipal systems, private wells generally aren’t monitored on a routine schedule by a public agency. So the big question becomes: what exactly should you test for—and how do you know you’re not missing something important?
This guide is designed to be a practical, real-world checklist you can actually use. It covers the most common contaminants, what they mean, when to test, and what to do if results come back high. The goal isn’t to make you paranoid—it’s to help you be confident that the water coming out of your tap is the water you want your household drinking, cooking with, and bathing in.
Even if you’ve tested before, it’s worth revisiting your approach. Well water can change over time due to weather, seasonal runoff, construction nearby, aging plumbing, or changes in the aquifer. A smart testing plan is less about doing everything all at once forever, and more about building a routine that fits your property and your risk factors.
Start with a quick “risk snapshot” of your well and property
Before you pick up a sample bottle, take ten minutes to think about what’s around you. Wells don’t exist in isolation. Your land use, your neighbors, and even your home’s plumbing can influence what shows up in your water.
Ask yourself a few simple questions: Is your well shallow or deep? Is it a dug well, driven point, or drilled well? Are there farms, septic systems, or busy roads nearby? Have you had flooding, heavy rains, or drought conditions lately? Each “yes” can point to a different set of tests to prioritize.
It also helps to consider who lives in the home. If you have infants, people who are pregnant, or anyone with compromised immunity, it’s wise to be more proactive with bacteria and nitrate testing. If someone in the home has sensitive skin or respiratory issues, you may also care more about things like hardness, iron, manganese, and sulfur odors—even if they’re not always a direct health threat.
How often should you test a private well?
There’s no single schedule that fits every well, but there are some practical baselines. Many homeowners do a broad screening once a year and then add targeted tests based on local concerns or any changes in taste, smell, or appearance. If you’ve never tested—or it’s been years—starting with a more comprehensive panel is usually the fastest way to get your bearings.
At minimum, most well owners should test for coliform bacteria and E. coli annually, and nitrates at least annually if there are infants or agricultural influences nearby. Beyond that, think of testing as a combination of routine checks and “event-based” checks.
Event-based testing is when you test because something happened: flooding, a well repair, a new baby in the home, a change in water color/odor, or a neighbor’s contamination issue. These are the moments when water quality can shift quickly, and catching it early can prevent bigger problems.
The core health-and-safety checklist (the tests most wells should start with)
Total coliform and E. coli (bacterial contamination)
If you test for only one thing, make it bacteria. Total coliform bacteria are a broad indicator group; they don’t always mean you have a serious problem, but they can signal that surface water or contaminants are getting into the well. E. coli is more specific and can indicate fecal contamination—something you want to treat as urgent.
Common causes include a cracked well cap, poor well construction, a compromised casing, or contamination from nearby septic systems—especially after heavy rain or flooding. Even a small pathway for surface water can introduce microbes into a well.
If coliform is present, the next steps typically include confirming with a repeat test, inspecting the wellhead, and considering shock chlorination or other disinfection strategies. But don’t stop at “we shocked the well”—you’ll want follow-up testing to confirm the fix actually worked.
Nitrates and nitrites (especially important for infants)
Nitrates are one of the most important well-water tests for families with babies. Elevated nitrate levels can cause “blue baby syndrome” (methemoglobinemia), which reduces the blood’s ability to carry oxygen. It’s serious, and it’s preventable with good testing habits.
Nitrates often come from fertilizer runoff, animal waste, or septic systems. Shallow wells and wells near agricultural areas are at higher risk, but nitrates can show up in suburban and rural settings too—especially where lawns are heavily fertilized or septic density is high.
If nitrates are elevated, boiling the water won’t help (it can actually concentrate nitrates). Treatment typically involves reverse osmosis or another properly designed system, and you’ll want to identify potential sources so the problem doesn’t worsen over time.
pH, alkalinity, and corrosivity (the “plumbing and metals” connection)
pH isn’t just a chemistry number—it affects how your water behaves in your plumbing. Low pH (acidic water) can be corrosive, which may lead to pinhole leaks, blue-green staining, and increased metal leaching from pipes and fixtures.
Corrosive water is one of the hidden ways contaminants enter your water after it leaves the well. Even if the groundwater is “clean,” the wrong pH and alkalinity balance can pull metals like copper and lead into your drinking water.
Testing pH and alkalinity helps you decide if you need neutralization or corrosion control. It also provides context for interpreting other results—especially metals—because the same metal level can mean different things depending on the water’s chemistry.
Lead and copper (especially in older homes)
Lead is one of those contaminants where “a little” still matters. It can impact brain development in children and contribute to health issues in adults. Private well owners sometimes assume lead is a “city water” issue, but lead can be present in older plumbing materials, solder, fixtures, and even some well components.
Copper is essential in small amounts, but elevated copper in drinking water can cause gastrointestinal discomfort and is also a clue that your water may be corrosive. Blue-green staining on sinks or tubs can be a sign, but testing is the only way to know for sure.
If you’re testing for lead, sample timing matters. A “first-draw” sample after water sits in the pipes overnight can show worst-case exposure. A flushed sample can help distinguish whether the source is household plumbing versus the well itself.
Metals and minerals: not always dangerous, but often disruptive
Arsenic (a high-priority test in many regions)
Arsenic is naturally occurring in some bedrock and can show up in groundwater without any obvious taste or smell. That’s what makes it tricky: your water can look perfectly clear and still contain levels that aren’t ideal for long-term consumption.
Because arsenic risk varies by geology, it’s worth checking local guidance and talking to a lab or water professional about whether your area has known arsenic patterns. If you’re unsure, testing is the simplest way to remove guesswork.
If arsenic is detected, treatment options may include adsorption media, reverse osmosis (for point-of-use), or other systems depending on the arsenic form and concentration. Follow-up testing after installation is key to confirm performance.
Iron and manganese (staining, taste, and appliance headaches)
Iron and manganese are classic “well water problems.” They can cause reddish-brown or black staining, metallic taste, cloudy water, and buildup in pipes. They’re often more of a nuisance than a direct health concern at typical levels, but they can still make water unpleasant and shorten the life of appliances.
Manganese can be a bigger deal for households with young children if levels are high, and it can contribute to dark staining and sediment. Iron bacteria can also create slimy buildup and odors, which is a different issue than dissolved iron.
Testing helps you distinguish between dissolved metals, particulate forms, and bacterial issues. That distinction matters because treatment can range from simple filtration to oxidation systems to specialized approaches for iron bacteria.
Hardness (calcium and magnesium)
Hard water isn’t usually a health risk, but it’s a daily-life issue. It can leave scale on faucets, reduce soap effectiveness, cause spots on dishes, and create buildup in water heaters and plumbing.
Hardness can also interact with other treatment systems. For example, some filtration media perform better when hardness is addressed, and scale can reduce the efficiency of fixtures and appliances over time.
A basic hardness test gives you a clear picture of whether a softener would be helpful—and whether the benefits (less scale, longer appliance life) match your household priorities.
Sodium (especially for low-sodium diets)
Sodium in well water can come from natural sources, road salt, or water softeners (which exchange hardness minerals for sodium). For many people, it’s not a major concern, but it can matter if someone in the home is on a sodium-restricted diet.
If you already have a softener or you’re considering one, testing sodium can help you make informed choices. Some households opt for potassium chloride instead of sodium chloride, or they install a separate drinking-water tap with a different treatment method.
Knowing your baseline sodium level also helps you track changes over time—especially in areas where road salt usage is heavy in winter.
Chemicals that can sneak in: fuels, solvents, and household-related contaminants
Volatile organic compounds (VOCs)
VOCs are a category of chemicals that include gasoline components, industrial solvents, and other compounds that can enter groundwater through spills, leaking tanks, or improper disposal. They’re not present in every well, but when they are, they matter.
Some VOCs have noticeable odors, but many do not. That’s why testing is important if your property is near a former industrial site, a gas station, a busy roadway corridor, or if you know of any historical dumping in the area.
If VOCs are detected, treatment often involves activated carbon or aeration, depending on the specific compounds and concentrations. Because VOCs are a broad category, a targeted VOC panel is usually the best approach rather than guessing.
Pesticides and herbicides
If you live near agricultural land, orchards, golf courses, or areas with heavy lawn care, pesticides and herbicides can be worth testing for—especially if your well is shallow or you’ve had heavy rainfall and runoff.
These compounds are diverse, so testing is often guided by what’s used locally. A lab can help you choose a panel based on regional patterns, or you can start with a broad screen if you’re unsure.
Even if results come back clean, having a baseline is useful. It lets you compare future tests and provides peace of mind when land use around you changes.
PFAS (“forever chemicals”)
PFAS have become a major water topic because they persist in the environment and have been linked to health concerns at very low concentrations. They can enter groundwater near certain industrial sites, airports, firefighting foam usage areas, and some landfills.
PFAS testing can be more expensive than basic panels, so it’s often prioritized based on proximity to known sources or state guidance. If your area has documented PFAS detections, it’s worth taking seriously even if your water looks and tastes fine.
If PFAS are detected, treatment commonly involves specialized activated carbon, ion exchange, or reverse osmosis for drinking water. As with any treatment, post-install testing is essential to confirm reduction.
Radiological and gas-related issues: the ones you can’t see
Radon in water
Radon is a naturally occurring radioactive gas that can dissolve into groundwater. When water is used for showering, washing dishes, or doing laundry, radon can be released into indoor air. In some areas, radon in water can meaningfully add to overall radon exposure.
Testing for radon in water is especially relevant if your home already has elevated radon in air, or if your region is known for radon risk. It’s also a good example of why “no smell, no taste” doesn’t equal “no problem.”
If your results are high, one possible treatment approach is a radon water aeration system, which is designed to strip radon out of the water before it reaches your taps. The right solution depends on your levels and your home’s setup, and it’s worth pairing water testing with an indoor air radon test for the full picture.
Uranium and gross alpha/beta screening
In some geologies, uranium can be present in groundwater. Like arsenic, it may show up without any obvious sensory clues. Testing is the only way to know, and it’s often recommended in areas with known occurrences.
Some homeowners start with a gross alpha/beta screening test, which can indicate whether more specific radiological testing is needed. If gross alpha is elevated, the lab may recommend uranium testing or additional analyses.
Treatment options vary, but can include reverse osmosis for drinking water or other systems depending on the contaminant and concentration. Because radiological results can feel intimidating, it helps to work with a lab that can clearly explain what the numbers mean.
“Nuisance” contaminants that still deserve a spot on your checklist
Hydrogen sulfide (rotten egg odor) and sulfur-related issues
If your water smells like rotten eggs, hydrogen sulfide gas is a common culprit. Sometimes it’s naturally occurring, and sometimes it’s related to sulfur-reducing bacteria. The smell can be stronger in hot water, which can make it feel like the water heater is the problem—even when the source is the well.
While hydrogen sulfide at typical household levels is often more of a nuisance than a direct health risk, it can make water unpleasant and can contribute to corrosion in plumbing. It can also occur alongside iron or manganese issues.
Testing can help determine whether you’re dealing with dissolved gas, bacterial activity, or both. That matters because treatment might involve aeration, oxidation/filtration, or disinfection strategies depending on the cause.
Turbidity, sediment, and color
Cloudy water, visible particles, or changes in color are common reasons people decide to test. Turbidity can spike after storms, well work, or seasonal changes. Sediment can clog fixtures, wear out appliances, and reduce the effectiveness of other treatment systems.
Even when sediment isn’t harmful on its own, it can be a warning sign that surface water is entering the well or that the well is producing fine material. It can also shield bacteria from disinfection, which is one reason it’s taken seriously in water treatment.
A simple turbidity or total suspended solids test can help quantify what you’re seeing. Pairing that with a well inspection can help you decide whether you need a sediment filter, a well repair, or both.
Total dissolved solids (TDS) and conductivity
TDS is a general measure of dissolved minerals and salts in water. It doesn’t tell you exactly what’s in the water, but it can be a helpful “big picture” metric—especially if you’re tracking changes over time.
High TDS can affect taste and may indicate that certain minerals are elevated. Conductivity is closely related and can also be used as a quick indicator that something has changed in your water chemistry.
If your TDS is high, it doesn’t automatically mean the water is unsafe, but it can be a reason to look more closely at specific ions (like sodium, chloride, sulfate) and at whether there’s a local source influencing your well.
Don’t forget these “situational” tests (they matter a lot in the right context)
Chloride (road salt, seawater influence, and taste)
Chloride can come from road salt, water softeners, or natural sources. In coastal areas, it can also be an indicator of saltwater intrusion. In winter climates, chloride can rise over time if salt storage or heavy road salting is common nearby.
Chloride can affect taste and contribute to corrosion, especially when combined with other factors. It’s also a useful tracer for human impact on groundwater, since it often increases with development.
If you see rising chloride over multiple tests, it’s worth investigating potential sources and considering protective steps—like improving wellhead protection or adjusting salt storage practices on the property.
Sulfate (taste and digestive upset at higher levels)
Sulfate can occur naturally and may contribute to a bitter taste. At higher levels, it can have a laxative effect, especially for people not used to it. It can also interact with plumbing and contribute to scale or corrosion depending on overall chemistry.
Because sulfate is part of a broader mineral profile, it’s often tested alongside other ions. If you’re already doing a general chemistry panel, it’s a low-effort add-on that can explain taste or household complaints.
If sulfate is elevated and bothersome, treatment might include reverse osmosis for drinking water or other approaches depending on your overall water profile.
Fluoride (naturally occurring in some wells)
Fluoride is sometimes naturally present in groundwater. Some people want to know their fluoride level for dental-health context, while others prefer to minimize fluoride exposure. Either way, testing gives you clarity.
Because fluoride is odorless and tasteless at typical levels, it’s not something you can detect without a lab result. It’s also not always included in basic panels, so you may need to request it specifically.
If fluoride is high and you want to reduce it, point-of-use reverse osmosis is a common option. If fluoride is low and you care about dental benefits, that’s a conversation to have with your dentist rather than trying to “dose” your well.
How to choose the right test package without overpaying
It’s easy to get overwhelmed by lists of contaminants, especially when labs offer dozens of panels. The trick is to combine a solid baseline with targeted add-ons based on your risk snapshot. That way you’re not paying for obscure tests you don’t need, but you also aren’t skipping the big ones.
A practical approach for many households is: (1) annual bacteria and nitrate, (2) a broader “baseline” panel every few years (metals, minerals, general chemistry), and (3) targeted tests like PFAS, VOCs, radon, or pesticides when local conditions suggest it.
If you’re in New England and you’re trying to build a thorough plan, it can help to look at services that bundle multiple tests into a coordinated strategy. For example, homeowners exploring comprehensive water quality testing NH often do so because they want a clearer view of the full water profile rather than chasing one issue at a time.
Sampling tips that make your results more reliable
Use the right bottles and follow the lab’s instructions exactly
Water testing is one of those situations where small details matter. A sterile bottle is required for bacteria testing, and preservatives may be required for metals or VOCs. If you use the wrong container or rinse it out, you can invalidate the test.
Pay attention to holding times too. Some samples need to reach the lab quickly—sometimes within hours. Plan your sampling day so you can drop off or ship immediately.
If you’re doing multiple tests, label everything clearly and keep a simple log: date, time, which tap, whether it was first-draw or flushed, and any recent events like heavy rain or plumbing work.
Choose the right tap and sample type (first-draw vs flushed)
For metals like lead and copper, a first-draw sample after water sits in the pipes can reveal whether your plumbing is contributing contamination. For general well-water quality, a flushed sample can better represent the groundwater itself.
For bacteria, you typically want a sample that reflects your drinking water source without contamination from the faucet aerator. Many labs recommend removing the aerator and disinfecting the spout before sampling.
If you have treatment equipment installed, decide whether you’re testing raw well water, treated water, or both. Testing both can be really helpful: raw water tells you what you’re dealing with, and treated water confirms whether your system is doing its job.
Time your testing around weather and seasonal changes
Some wells show seasonal patterns. Spring runoff can increase turbidity or bacteria risk. Late summer drought can concentrate minerals. Big storms can change groundwater flow paths and introduce surface influences.
If you want a realistic picture of risk, consider testing at least once during a “high risk” time of year in your region. If your well has ever tested positive for bacteria, it’s especially useful to test after heavy rains.
Over time, keeping results in a folder (or spreadsheet) helps you see trends. A slow increase in chloride or sodium might not stand out on a single report, but it becomes obvious across multiple years.
What to do when results come back high
Separate “urgent” from “fixable over time”
Some results require fast action. E. coli, high nitrates (especially with infants), and certain chemical detections can mean you should stop using the water for drinking right away until you have a plan. In those cases, use bottled water and contact a qualified professional for next steps.
Other issues—like hardness, iron staining, or slightly off pH—are usually not emergencies. They’re still worth addressing, but you can take the time to compare treatment options and plan a budget-friendly solution.
If you’re unsure how serious a result is, ask the lab to explain the health-based standard (if one exists), the aesthetic guideline, and what the typical treatment pathway is. Clear interpretation is half the battle.
Confirm with follow-up testing before and after changes
It’s tempting to jump straight into buying equipment, but confirmation matters. False positives can happen due to sampling errors, and some contaminants fluctuate. A second test can help you avoid treating a problem you don’t actually have.
After installing any treatment system, test again to confirm performance. This is especially important for contaminants like arsenic, PFAS, nitrates, and radon, where the goal is a measurable reduction.
Also remember that treatment systems need maintenance. Filters need replacement, media needs regeneration or change-out, and UV systems need bulb changes. A good plan includes ongoing monitoring, not just a one-time fix.
If you’re on municipal water, you can still borrow this checklist mindset
This article is focused on private wells, but plenty of people on city water still want reassurance—or they want to improve taste, reduce chlorine, or address specific concerns like lead from household plumbing. The same idea applies: start with your goals, identify your risks, and then choose targeted testing and treatment.
Municipal water is treated and monitored, but it can still pick up issues in building plumbing, and some people simply prefer an extra layer of filtration at home. If you’re exploring options in southern New Hampshire, resources around city water filtration Bedford NH can be useful for understanding common treatment approaches and what they’re designed to address.
Whether you’re on a well or city supply, the best outcomes usually come from matching the solution to actual data. Testing first keeps you from guessing—and helps ensure you’re spending money where it truly improves your water.
A practical “bring-it-to-the-lab” checklist
If you want a simple starting point, here’s a practical checklist you can use when calling a lab or water professional. Think of it as a menu you can customize based on your property snapshot and any known regional concerns.
Annual (or more often if risk is high): total coliform, E. coli, nitrates (and nitrites if recommended).
Every few years (baseline profile): pH, alkalinity, hardness, iron, manganese, sodium, chloride, sulfate, TDS/conductivity, plus metals like lead and copper (especially if plumbing is older).
As needed based on location and history: arsenic, radon in water, uranium/gross alpha, VOCs, pesticides/herbicides, PFAS, and any other locally relevant contaminants.
The best part about having a checklist is that it turns water testing from a vague “we should probably do that” into a manageable routine. And once you have a few rounds of results, you’ll start to understand your well’s personality—what stays stable, what changes seasonally, and what to keep an eye on long-term.