Well Water Testing Guide: Annual Checklist for Wells
By SubcontractorHub Editorial Team·Published October 2026
Short version: once a year, test a private well for total coliform and E. coli, nitrate, pH, total dissolved solids, hardness, iron, and manganese. Add sulfur if it smells like rotten eggs. Add arsenic, radon, or PFAS when your area calls for them, not because a national page guessed. Symptoms pick the extra tests. The lab report picks the treatment order. A softener is not the first answer to every line.
A private well does not get the sampling a city plant does. The owner is the operator, which means the owner usually tests after something has already gone wrong. This guide is the list to run before that, the times to run it early, and the path from a symptom to a test to a treatment stage. It points at the deeper pages instead of repeating them. Start with bacteria in coliform bacteria in well water and with the metal that stains in iron filter for well water.
The Annual Panel
These seven are the tests that change what you install, or that tell you not to install anything. Local health departments add others. If their sheet and this table disagree, follow the department. They know the aquifer.
| Test | Why it is on the list | Where to go next |
|---|---|---|
| Total coliform and E. coli | A pathway, and a fecal marker. No taste. Retest and shock are a different article. | Coliform bacteria in well water |
| Nitrate (and nitrite) | The EPA public-system limit is 10 mg/L as nitrogen. Private wells use that number as the health benchmark. Check the unit on the report. | Nitrates in well water |
| pH | Acidic water eats copper and slows iron oxidation. The secondary range people aim for is roughly 6.5 to 8.5. | Copper in water, and a neutralizer if pH is low |
| Total dissolved solids | A conductivity picture of how much is dissolved. The secondary standard is 500 mg/L. High TDS is not, by itself, a treatment prescription. | System selector, after you know which ions are high |
| Hardness | Drives the softener. Report it as calcium carbonate, not raw calcium, or the grains will be wrong. | How to test water hardness |
| Iron | The staining line this site uses is 0.3 ppm. Form (clear-water or rusty) matters as much as the number. | Iron filter for well water |
| Manganese | EPA secondary standard 0.05 mg/L, with a separate health advisory discussed on the manganese page. Black stains. | Manganese in well water |
Bacteria and nitrate are the every-year pair because a cracked cap or a wet spring can change them without changing the taste. Hardness, iron, and manganese are worth repeating on a rhythm too, especially after you install treatment, so you know the equipment is still matched to the water. A single test the year the house was built is not a current report.
Read the units before you compare two labs. Nitrate as nitrogen and nitrate as the nitrate ion are not the same number. The trap, and the 10 mg/L benchmark, are explained in nitrates in well water. Hardness in ppm is not hardness in grains. Convert it with the water hardness converter before you type it into a softener valve. The field method for a strip is in how to test water hardness.
Sulfur, and the Tests You Add Locally
Hydrogen sulfide is the rotten-egg gas. It may not be on a standard metal panel, and it escapes from a sample bottle if you treat it like a hardness test. If you smell it, say so when you order, and read why water smells like rotten eggs before you buy a filter. Smell on the hot side only is often the water-heater anode, which is a different repair from an aquifer problem.
Arsenic has no taste. The EPA limit used on this site is 10 ppb for public systems, and private-well owners borrow that benchmark because nobody samples the well for them. Speciation, arsenic III versus arsenic V, decides whether a filter will work. That is the whole subject of arsenic in well water. Add it when your state is known for arsenic in groundwater, or when the health department names it, not on a whim.
Radon in water is a breathing problem as much as a drinking problem, because showers and laundry release it into indoor air. Where granite and similar rock make it likely, order a radon-in-water test with the right vial. The methods and the limits that were proposed and never finalized are in radon in water. A coliform bottle does not measure radon.
PFAS, the fluorinated chemicals associated with some industrial sites, airports, and firefighting foam, belong on the order when a state program or a nearby site says so. This site does not have a PFAS treatment page, and this guide will not invent a removal percentage or a national “safe” number for a private well. Ask the county what they want analyzed, use their lab list, and do not substitute a hardness strip.
When to Test Sooner Than Next Year
- A new well, or a house you just bought, before anyone treats the first result as normal.
- After a flood, a cracked cap, or any day surface water stood over the wellhead.
- After the pump is pulled or the casing is opened. Bacteria often show up because the well was open, not because the aquifer changed.
- When a baby is on the way or an infant will drink formula mixed with the water. Nitrate is the reason, not taste.
- When taste, smell, or color changes, or when a treatment system that used to work suddenly does not.
- When a neighbor, a farm, or an industrial site nearby becomes a reason your health department names an extra contaminant.
A positive bacteria test is its own clock. Resample, find the pathway, shock, and test again. The sequence is how to shock a well plus the coliform article. Do not wait for the anniversary.
Symptoms, Then Tests, Then Treatment Order
What you see gets you to the right bottle. It does not replace the bottle. Use the map, then confirm.
| What you notice | Test it | Then |
|---|---|---|
| No smell, no stain, family drinks it | Still run bacteria and nitrate once a year. Invisible contaminants are the point of the lab. | Do not install a softener 'just in case' before the test. |
| Orange or brown stains | Iron, and a look for iron-bacteria slime in the toilet tank. | Iron filter guide if it is metal. Iron bacteria guide if it is gel. |
| Black or gray stains | Manganese, plus iron, because they travel together. | Manganese guide. Do not sell an iron-only air filter and hope. |
| Rotten eggs | Hydrogen sulfide, and whether the smell is on hot only. | Rotten-egg guide. Hot-only often means the anode, not the aquifer. |
| Blue or green stains | pH and copper. First-draw versus flushed samples tell pipe from well. | Copper in water. A neutralizer before you blame the fixture. |
| Cloudy or gritty | Sediment. Let a glass sit. Sand settles. Air clears from the bottom up. | Sediment filter sizing, and a well check if sand is new. |
Treatment order is where good tests go to waste. A typical well train, once the numbers justify each stage, runs like this. Sediment first, so sand does not pack everything else. A neutralizer next if pH is too low for the iron step you chose. Iron and sulfur filtration, or chemical injection plus a filter, before the softener. The softener on the compensated hardness, not on a guess. Ultraviolet light last among the whole-house stages, because it needs clear water. Reverse osmosis at the kitchen sink for nitrate and for drinking water you do not want to send through the softener. The well water treatment system selector builds that list from the numbers you type.
Sizing is separate from sequencing. Peak flow and backwash decide the iron shell in the iron filter sizing calculator. The well's ability to hold that flow is the well recovery rate calculator. UV dose is the UV sizing calculator. Softener grains are the softener sizing calculator. None of those tools replace the lab.
How to Take a Sample the Lab Can Use
Use the bottle the lab sent, for the test you ordered. Bacteria bottles are sterile. Metal bottles may contain acid. Do not rinse them. Take the aerator off for a bacteria sample, disinfect the tap if the instruction says to, run the cold water, and fill without touching the rim. Keep the sample cool if they told you to, and get it to the lab inside the holding time printed on the sheet. A bottle that sat in a hot truck over a weekend is not a cheap way to save a trip. It is a wasted test.
Decide where the sample represents. The wellhead, before filters, is the source. The kitchen tap is what the family drinks. After a new softener, a sample at the tap tells you whether the valve was programmed. Label the point on the form. A dealer who cannot say where the water was taken cannot explain a result that disagrees with last year.
Home strips still have a job. They are how you screen hardness and pH on a service call and how you notice that iron came back between lab years. They are not how you clear a well for an infant, and they are not how you tell arsenic from “the water tastes fine.”
What the Dealer Keeps
The report is the sales document and the service document. Attach it to the customer, note the sample point and the date, and quote only the stages the numbers support. A year later the retest is a visit you already earned, not a cold call. Iron bacteria, if the toilet tank is slimy, change the quote from “one filter” to shock plus oxidation plus a filter. That diagnosis is iron bacteria in well water.
Water treatment contractor software is where that file lives next to the proposal and the next service date. If you want to see a lab panel turn into a staged quote, book a demo. This page does not list lab prices. They move by state and by how many extra contaminants the county adds.
Frequently Asked Questions
What should you test well water for every year?
The standing annual list is total coliform and E. coli, nitrate, pH, total dissolved solids, hardness, iron, and manganese. Add hydrogen sulfide when the water smells like rotten eggs. Add arsenic, radon, or PFAS when your state, your county, or a known local source says those belong on a private-well panel. One national bottle does not cover every aquifer.
How often should a private well be tested?
Once a year for bacteria and nitrate is the usual baseline, because those can change. Test again after a flood, after the well is opened for service, when a baby is expected, and whenever taste, smell, or color changes. Metals and radon can be less frequent once you have a baseline, unless something nearby changes. Your health department's list outranks a generic schedule.
Can you trust a home test kit for well water?
Strips are useful for hardness, pH, and a rough iron check while you are standing at the sink. They are a poor final word on bacteria, nitrate, arsenic, or PFAS. Those need a certified lab and a clean sample. Use a strip to decide whether to book the lab, not to tell a customer the water is safe.
Which test matches which symptom?
Orange stains point at iron. Black or gray stains point at manganese. A rotten-egg smell points at hydrogen sulfide. Blue-green stains point at copper and low pH. Cloudy water can be sediment or air. None of those symptoms reveal nitrate, arsenic, or coliform. No taste is not a clean test. Map the symptom to a test, then map the test to treatment in the right order.
Does a softener fix a bad well test?
A softener removes hardness and a limited amount of clear-water iron. It does not disinfect, it does not remove nitrate, and it is a poor primary filter for manganese or arsenic. Treatment order follows the test: sediment and pH, then iron and sulfur, then the softener, then ultraviolet light if bacteria need a lasting barrier, with reverse osmosis at the sink for nitrate and some other dissolved contaminants.
Who is responsible for testing a private well?
The owner. Public water systems are sampled under federal and state rules. A private well is not on that schedule unless a lender, a health department, or a local ordinance requires a sample at a sale or a new-baby visit. A dealer who tests and keeps the report is doing the job the homeowner will not do alone.
Related Guides & Tools
- Coliform Bacteria in Well Water
- Nitrates in Well Water
- How to Test Water Hardness
- Iron Filter for Well Water
- Manganese in Well Water
- Why Water Smells Like Rotten Eggs
- Arsenic in Well Water
- Radon in Water
- Copper in Water
- Well Water Treatment System Selector
- Water Hardness Converter
- Water Treatment Contractor Software
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