There are basically two options: the state lab and private well testers.
There are 14 private labs in New Hampshire certified by the state to perform well water tests, (which you can find by clicking here) as well as numerous labs in neighboring states. There is also the state’s lab, (again, click here for the link) which is used for all sorts of testing done on public water systems, but can also be accessed by private homeowners.
In both cases, you have to do some of the leg-work yourself. You request the special sterile containers, which are typically sent to your home through the mail, and fill them yourself and then return them to the lab (usually not through the mail).
The state recommends doing the tests after a big rainstorm, because that’s when you're most likely to see problems. If the protections built into the well design are going to be overwhelmed, or if contaminants that aren’t easy to get flowing are going to move, it’s most likely to be obvious when there’s a lot of water. The state also recommends testing your well every three to five years, because conditions in the bedrock can change-- you might draw down water coming from a certain area of the aquifer, and water might start flowing in from another rock formation, bringing with it new baggage.
There are other reasons why re-testing might be a good idea:
· If you live in a heavily developed area near something that involves hazardous chemicals. Living close to a gas station or auto body shop is a perfect example.
· If you have had recent well repairs. However, this should be done after the well is flushed and cleaned. Some wells will test positive for bacteria if they weren’t cleaned after someone with dirty hands did the work.
· If you have high contaminants to start with… you know just to be safe.
· If there is something weird going on with your water, like it runs a different color after it rains, or a funny taste develops, or it suddenly becomes cloudy.
· Noticeable variations in quality such as a change after a heavy rain or an unexplained change in a previously trouble-free well. For example, funny taste, cloudy appearance, etc.
Once a basic test is done, further testing can sometimes be needed. For instance, there are two kinds of arsenic – called species – and which type is in your water changes what treatment options will work for your home.
And if at all in doubt, call a water professional.