A water quality testing lab gives you the one thing a home kit cannot: a defensible number, produced on calibrated instruments by an accredited facility, that an installer or a health department will accept. Using one well is mostly about three things: choosing a certified lab, ordering the right panel, and taking the sample exactly as instructed.
Certification is what you are paying for
Look for a laboratory certified by your state for drinking water analysis, since certification is what makes a result admissible for a mortgage, a real estate transaction or a health department query. Many state health departments and land grant university extension services publish a list of certified labs for their state, and some run testing programs directly. A lab that arrives as a mail-order kit from a retailer may still be certified, but the certification is worth checking rather than assuming, because it is the difference between a number and an opinion.
Ordering the right panel
A basic well panel usually covers total coliform bacteria and E. coli, nitrate, nitrite, pH, hardness, iron, manganese, total dissolved solids and sometimes sulfate and chloride. Add arsenic, lead, uranium or radon where local geology or your neighbors' results suggest it, and add specific contaminants where an industrial or agricultural source sits nearby. Testing everything at once is expensive and unnecessary; testing too narrowly is how a problem gets missed. Ask the lab what is common in your county, since they see the local pattern every week.
Sampling is where most results go wrong
Use the bottles the lab sends and nothing else, since bacteria bottles contain a preservative and metals bottles may be acid-washed. Do not rinse a bottle that came with preservative in it. For a bacteria sample, sanitize the tap, remove the aerator and follow the instructions to the letter, because a contaminated sampling technique produces a positive result about your kitchen, not your well. Bacteria samples have a short hold time, so post or deliver them the same day and avoid mailing on a Friday when they will sit in a depot over the weekend.
Who most needs a lab result
Private wells are not federally regulated under the Safe Drinking Water Act, which means no agency tests them for you. Around 15 percent of the US population, over 43 million people in more than 23 million households, rely on private wells, and a USGS study of 2,100 private wells found about one in five carried at least one contaminant above a human-health benchmark. That is the case for annual testing in plain terms. City customers usually need a lab only for what their own pipes add. Our water testing lab near me guide covers finding a certified facility locally.
Questions people ask about water quality testing lab
How much water does a lab need?
The lab supplies bottles sized for the panel you ordered, typically a small sterile bottle for bacteria and larger ones for chemistry. Fill each to the line marked and no further.
How long do results take?
Bacteria results are usually back within a few days because the culture takes time. Chemistry panels commonly take one to two weeks depending on the lab's queue and the parameters ordered.
Can I use the free test a softener dealer offers?
It is useful as a screen for hardness and iron, and it is not a certified result. For anything health related, or for a property transaction, use a state certified laboratory.
How often should a private well be tested at a lab?
Annually for bacteria and nitrate at minimum, and again after flooding, well repairs or any change in taste, smell or appearance, since those signal something has changed at the source.