Best home water test kits

How to choose

Start with where your water comes from

EPA regulates public supplies, but homeowners are responsible for testing and treating private wells.⁵ A well can look fine and still fail. In a USGS survey of domestic wells, about 23 percent of the 1,389 wells checked for most contaminants had at least one above an EPA limit or a USGS health screening level.²²

A utility's water report describes the water system, not your plumbing. City homes with a clean report and no lead service line, lead solder or older brass fixtures may only need one lab lead test.¹

How many tests you need

Get one lab test per water source when you move in. On a well, repeat it every year for total coliform bacteria, nitrate, total dissolved solids and pH, as EPA and CDC advise, and add arsenic and lead on the first test.^{2 3 7 22} Test right away if you repair the well, conditions nearby change, or the water's odor, color or taste changes. EPA suggests testing more often if small children or older adults live in the house, or if someone there is pregnant.²

Treat a flooded well as suspect until a lab says otherwise. After Hurricane Harvey, microbial contamination was 1.7 to 2.5 times more likely in flooded wells, or where residents felt the water was unsafe, among 8,822 wells sampled, and disinfection did not always clear it. Test again after you chlorinate.²³

On a well, pay for the likely problems first

EPA's yearly list leaves out things USGS found often. Nitrate, arsenic, manganese, strontium and gross alpha radioactivity each went over a health benchmark in about 5 to 7 percent of wells, while organic compounds did so in 0.8 percent.²² So metals, nitrate and radioactivity usually deserve your money before a long list of solvents, unless you have a nearby source. Wells near intensive farming should add pesticides.² Ask your local health department what's common in your area.³

Try a local certified lab before a mail-in kit

EPA and CDC both say to use a state-certified lab, and EPA links each state's list.^{2 3 24} A local health department may even test a private well for free, and dropping a bottle at a local lab avoids the shipping risk for bacteria.^{2 10} University programs can cut the cost too: Virginia Tech's put participant savings at about 78 percent against its estimate of commercial prices.²⁵

Mail-in services are easier to order and read, but they aren't the same thing. Tap Score calls its packages informational, says some methods may not meet your state's compliance rules, and offers certified testing separately. It also warns that proxy results on its Essential and Advanced kits, including nitrate and uranium, could be off by as much as twice the reported value.¹⁵ If a state, lender or home sale needs the result, confirm the lab's status first.

Don't choose by the number of tests

Kits advertise counts of 111, 114 or 200. Coverage of the right items matters more. Safe Home's 200 includes physical properties and calculated values, and it doesn't include a lab bacteria test, while neither Tap Score Advanced kit includes PFAS.^{11 26 27}

Use strips for hardness, not for safety

Virginia Tech researchers bought 16 brands of at-home lead kits on Amazon in 2018 and tried them against known lead levels. Twelve couldn't accurately read 150 micrograms per liter, ten times the 15 parts per billion action level the researchers used. Three yes-or-no strips did much better, at 82.1 percent accurate on water with only dissolved lead, but they fell to 28.6 percent when the lead was all particles.⁴ So a multi-parameter color strip can't rule out lead, and a yes-or-no strip is only a first look.

Metals show the same pattern. UMass Amherst researchers tried eight off-the-shelf kits and found that most worked best in deionized water. None of the multi-parameter kits detected low iron, while three of four single-parameter kits did, though their results were often off.^{28 29} If you use a home kit, one that tests a single thing is usually the better bet. Treat any metal result as a reason to call a lab.

Strips do have a place. San Francisco's utility found that its three kit brands agreed with the lab less than 60 percent of the time on hardness in its own soft water, but more than 80 percent of the time in water of moderate to high hardness. It still calls kit results an initial step.³⁰ If you only want your hardness before buying a softener, a cheap hardness strip is enough. Some review sites say their kits matched lab benchmarks, but they show no numbers, so the measured studies carry more weight.¹⁸

Take lead samples the right way

Send a first-draw sample, taken after the water has sat in the pipes, and ideally a flushed sample too. Ask for total lead, which counts particles as well as dissolved metal.^{7 31} Flushing helps but isn't guaranteed. In 2,146 samples from Virginia private systems, almost 20 percent of first draws were above 15 parts per billion. Flushing brought most systems below that, but some rose.⁷

A clean result lowers your concern, but it doesn't prove your plumbing is free of lead. In a 2024 simulation of 100,000 homes, one round of sampling caught lead spikes with 6.4 percent sensitivity, and it took seven rounds to reach 50 percent.³¹ Repeat the test if young children or a pregnant person drink the water.^{2 31}

Add PFAS or radon if they apply to you

PFAS are the long-lasting chemicals often called forever chemicals. USGS estimates at least 45 percent of US tap water has one or more of them, at similar levels in public supplies and private wells.⁵ Test for them if you live near a known source or your state flags them, because standard panels leave them out. Safe Home sells a separate PFAS kit, and Tap Score sells one too.^{16 32}

Radon in well water went over the lower of two proposed limits in about 65 percent of USGS's wells and the higher one in about 4 percent, so ask your state whether it matters where you live.²²