Best Well Water Test Kits: What to Test For and Where to Send It
Quick answer: the CDC says to test a private well at least once a year for total coliform bacteria, nitrates, total dissolved solids and pH, using a state-certified lab. A mail-in lab kit like the Tap Score Essential Well Water Test covers those plus iron, manganese, hardness, arsenic and lead, which is everything you need to choose a softener or filter. Your local health department can often test the basics or list certified labs near you. A DIY kit like the Watersafe Drinking Water Test is a quick screen, but its maker says it can’t certify water as safe.
Our picks:
- Best overall: Tap Score Essential Well Water Test (54 items, certified lab)
- Best for fuel, industrial or PFAS worries: Tap Score Advanced or Extended Well Water Test
- Often the simplest certified option: your health department or a state-certified lab
- Best DIY screen: Watersafe Drinking Water Test Kit (9 items at home)
- Best for bacteria retests: Watersafe Bacteria Water Test
How we chose: we haven’t used these kits ourselves. We compared what each one tests for with the CDC’s and Penn State Extension’s testing advice, using each maker’s own product pages and instructions.
What to test a well for, and when
Public water rules don’t cover private wells, so testing is up to you. The CDC’s yearly minimum is four tests:
- Total coliform bacteria. Coliforms usually won’t make you sick, but they get into water the same way as germs that do, such as from a sewage leak. A test for E. coli shows whether feces have reached the well.
- Nitrates, which can make people sick, especially babies. They come from fertilizers, septic systems, animal waste and farm runoff.
- Total dissolved solids (TDS), a measure of how much is dissolved in the water. High TDS can leave scale on pipes and appliances.
- pH. Water that’s too acidic or too basic can damage pipes, and damaged pipes can leach metals like lead.
The CDC also says to ask your health or environmental department which other contaminants matter where you live, such as arsenic, lead, radium, pesticides or VOCs (fuel and industrial chemicals). It recommends extra testing when:
- there are known well problems in your area
- there’s flooding, land disturbance or a waste disposal site near the well
- you repair or replace part of the well system
- the water’s taste, color or smell changes
- someone in the home becomes pregnant, or a child comes to live with you
What should you test your well for?
Tick everything that applies. You’ll get a test list and the type of kit that covers it.
Test for these 4 things
- Total coliform bacteria: the CDC’s yearly minimum.
- Nitrate: the CDC’s yearly minimum.
- Total dissolved solids: the CDC’s yearly minimum.
- pH: the CDC’s yearly minimum.
Kit that covers it: a state-certified lab, through your health department or a mail-in kit like the Tap Score Essential Well Water Test.
- Ask your health department which other contaminants, such as arsenic or radium, are common where you live.
The checklist follows the CDC’s and Penn State Extension’s well testing advice. It doesn’t replace your health department’s advice for your area.
Lab test or DIY kit?
| Certified lab (mail-in or local) | DIY test kit | |
|---|---|---|
| What the CDC recommends | Yes: a state-certified lab | Not as a replacement for a lab |
| How much it covers | From a basic panel to 100+ items | A handful of items, as color changes |
| Results | Measured amounts, in a report | Approximate ranges, or yes/no for bacteria |
| Bacteria | Sample must reach the lab fast; Penn State’s lab allows 30 hours | Read at home after up to 48 hours |
| Best for | The yearly test, home sales, choosing treatment | Quick checks between lab tests |
Compare the kits
| Kit | Type | Bacteria | Nitrate, pH, TDS | Iron, manganese, hardness | Hydrogen sulfide | Lead, arsenic | VOCs |
|---|---|---|---|---|---|---|---|
| Tap Score Essential | Mail-in lab, 54 items | Total coliform, E. coli | All three | All three | At-home strip | Both | No |
| Tap Score Advanced | Mail-in lab, 114 items | Total coliform, E. coli | All three | All three | At-home strip | Both | 50 VOCs and SVOCs, 7 petroleum compounds |
| Watersafe Drinking Water Test | DIY, 9 items | Yes/no, 48 hours | Nitrate and pH; no TDS | Iron and hardness; no manganese | No | Lead only | No |
| Watersafe Bacteria Water Test | DIY, bacteria only | Yes/no, 6–48 hours | No | No | No | No | No |
Our picks
Tap Score Essential Well Water Test
Tap Score, from SimpleLab, sends you bottles, instructions, a cold-shipping kit and a prepaid return label. It then routes your sample to a certified lab in its network. The Essential test covers the CDC’s four yearly tests plus the numbers you need to choose treatment, so one sample does both jobs.
- Tests for: 54 items, including total coliform, E. coli, nitrate, nitrite, pH, TDS, hardness, turbidity, iron, manganese, arsenic, lead, copper and uranium
- Hydrogen sulfide: measured at home with an included test strip
- Turnaround: 5 business days once the lab has the sample
- Shipping: 2-day shipping to the lab is included, and overnight options are offered at checkout
Good to know: Tap Score says its labs hold accreditations from ISO to NELAC and state programs. If you need results from a lab certified in your state, for a home sale for example, ask Tap Score which lab will run your sample before you order. Bacteria samples need to reach the lab quickly; Penn State’s lab, for example, starts testing within 30 hours of sampling.
See it at Tap ScoreTap Score Advanced and Extended Well Water Tests
If your well is near fuel tanks, a gas station, industry or a landfill, the CDC suggests asking about VOCs, the industrial and fuel-related chemicals the Essential test leaves out. The Advanced test adds them. The Extended test also adds PFAS and radiological tests.
- Advanced: 114 items, adding 50 VOCs and SVOCs, 7 petroleum compounds and 2 pesticides (fumigants such as 1,3-dichloropropene); 5 business days at the lab
- Extended: 142 items, adding 25 PFAS and 2 radiological tests; 12 business days at the lab
- Shipping: overnight to the lab is included with both
Good to know: the CDC notes these tests can be expensive, so ask your health department which chemicals are a concern locally before choosing the biggest panel.
See Advanced at Tap Score See ExtendedYour health department or a state-certified lab
The CDC says local and state health or environmental departments often test for nitrates, total and fecal coliforms, VOCs and pH, or can give you a list of state-certified labs nearby. The EPA keeps a list of each state’s lab certification office. A local lab can also take your sample in person, which makes the bacteria deadline easy to meet.
- Best for: the yearly bacteria and nitrate test, and results tied to your state’s certification
- Also ask: which contaminants are common in your area, and how to read your results
Good to know: not every lab runs every test, so check that yours offers iron, manganese, hardness and hydrogen sulfide if you’re choosing treatment.
Find your state’s certified labs (EPA)Watersafe Drinking Water Test Kit (The Original)
Watersafe, made by Silver Lake Research, screens for nine things at home with test strips, packets and a bacteria vial. Use it for a quick look between lab tests, or to see whether you have iron or hard water before you pay for a full panel.
- Tests for: lead, bacteria, copper, iron, nitrate, nitrite, pH, hardness and chlorine
- Bacteria: keep the vial at 70–90°F for 48 hours; purple means none detected, yellow means bacteria are likely
- Lead: Watersafe’s listing says it detects lead down to 5 ppb
Good to know: Watersafe calls it a screening test that can’t certify water as safe or unsafe. It doesn’t test TDS, manganese, hydrogen sulfide or arsenic. A positive result for bacteria, lead or nitrate needs a certified lab to confirm it.
Check price on AmazonWatersafe Bacteria Water Test
After a positive coliform test and shock chlorination, Penn State says to retest about 10 to 14 days later, then again two to three months after that. Watersafe’s bacteria vials are a cheap way to keep an eye on things between those lab tests.
- Sensitivity: down to 1 CFU per mL, per Watersafe
- Timing: may turn yellow (positive) in as little as 6 hours; wait 48 hours to confirm a negative
- Temperature: keep the vial between 70 and 98.6°F, out of direct sunlight
Good to know: it shows whether bacteria are present, not which kind or how many. Use a certified lab for the retests that decide whether you need ongoing disinfection.
Check price on AmazonHow to take a well water sample
A good sample matters as much as the lab. Follow your kit’s instructions first. Penn State Extension’s guidance for its own kit covers the basics:
- Take a lead sample first thing in the morning, from the faucet you drink from, before any water runs. The water should have sat in the pipes for at least six hours.
- For bacteria, remove the faucet aerator and run the cold water about five minutes.
- Keep the bacteria bottle sterile. Wear gloves, don’t touch the inside of the cap or the bottle’s rim, and don’t set the cap down.
- Fill only to the line. Many bacteria bottles hold a preservative that overfilling washes out.
- Keep samples cold and ship fast. Penn State’s lab has a 30-hour window from sampling to testing, so it says to sample just before the overnight shipping cutoff.
If your test finds coliform bacteria
The CDC says that if a test shows harmful germs or chemicals, consider drinking bottled water and contact your health department for help with next steps. For coliform bacteria, Penn State recommends shock chlorination, then a coliform retest about 10 to 14 days later and another two to three months after that. If bacteria come back in either retest, you’ll need continuous disinfection, such as a UV system. Our well water filtration guide explains which UV units are designed for that.
Using your results to choose treatment
- Iron, manganese or a sulfur smell: enter your numbers in our well water filtration picker.
- Hardness: see water softener hardness settings and our size calculator. To retest hardness yourself, see the best water hardness test kits.
- Hard water with iron: see the best water softeners for iron and for well water.
Frequently asked questions
How often should you test well water?
At least once a year for total coliform bacteria, nitrates, total dissolved solids and pH, according to the CDC. Test again after flooding, well repairs, or any change in the water’s taste, color or smell.
What does a well water test kit test for?
It depends on the kit. A basic lab panel covers bacteria, nitrate, pH and TDS. Larger panels, like Tap Score’s Essential, add metals such as iron, manganese, arsenic and lead, plus hardness. DIY kits usually cover a handful of items with color-change strips.
Are home water test kits accurate?
They’re screening tools. Watersafe says its kits give approximate results and can’t certify water as safe or unsafe. For results you can act on, the CDC recommends a state-certified lab.
How do I test my well water for iron?
A DIY kit like Watersafe’s shows roughly how much iron there is. To choose a filter, you need a lab number in ppm (mg/L) for iron and manganese. Tap Score’s Essential test includes both.
How do I test for hydrogen sulfide?
At home. Penn State says hydrogen sulfide must be tested at home, or the sample chemically stabilized before it goes to a lab. That’s why Tap Score includes an at-home strip for it.
Who tests well water near me?
Start with your local health or environmental department. The CDC says they often test for the basics or can give you a list of state-certified labs. The EPA also lists each state’s lab certification office.
Related guides
- Best well water filtration systems
- Why water smells like rotten eggs
- Best water softeners for well water
- Water softener hardness settings
- Best water softeners for iron
Sources
- CDC, Guidelines for Testing Well Water (July 2024).
- U.S. EPA, Protect Your Home’s Water and certification programs and certified laboratories.
- Penn State Extension, How To Use the Penn State Drinking Water Test Kit, Shock Chlorination of Wells and Springs (updated May 2025) and Hydrogen Sulfide (Rotten Egg Odor) in Water Wells.
- Tap Score, Essential, Advanced and Extended Well Water Test pages.
- Silver Lake Research, Watersafe Drinking Water Test and Bacteria Test Vial instructions.