If you are on a well, nobody is testing your water for you. No agency checks it, no report arrives in the mail, and the responsibility sits entirely with whoever owns the house. That is not a warning, it is just where the line is drawn — and in Sherborn, Dover, Wayland, and Upton it applies to a lot of houses. This is what a Metrowest well owner is actually responsible for, what the bedrock under this area has to do with it, and what treats what.
Less than most people assume. Massachusetts has no single statewide private-well testing mandate. There is no state-level schedule you are falling behind on and no form that goes anywhere.
What exists instead is local. Boards of health often set their own requirements, and the two moments that come up most commonly are at well completion and before a property sale. Total coliform bacteria and nitrate are the typical minimum in that testing.
The practical consequence is worth sitting with: between the day the well was finished and the day the house changes hands, the only person checking that water is you. A public water system is tested on a schedule and has to report to its customers. A private well has neither of those things behind it.
So for the rules that actually apply to your address, your local board of health is the authority. Requirements vary from town to town, and the board is the one that can tell you what yours expects and when.
Some of what turns up in a well has nothing to do with anything anyone did — it comes out of the rock the water sits in.
Arsenic occurs naturally in some Massachusetts bedrock formations. Uranium and radon are present in some areas as well, particularly where wells are drilled into granite or other crystalline bedrock. Radon in Massachusetts groundwater is a decay product of the uranium in the surrounding rock, which is why the two tend to be discussed together.
Here is the part that is specific to this area, stated plainly. USGS and MassDEP studied arsenic and uranium in private bedrock wells and focused on east-central Massachusetts, because arsenic concentrations in bedrock well water are elevated in that area. Metrowest sits in that region.
That is a reason to test. It is not a reason to be alarmed, and we are not going to write it that way. Elevated probability across a region is not a result for your well, and plenty of wells in this area test fine. The point is only that it is a live question here in a way it is not everywhere, and it is answerable.
MassDEP publishes an address-lookup map showing the probability of elevated arsenic and uranium in private bedrock wells. You can enter your own address and see what it says for your location. It is reachable from the private well pages at mass.gov/private-wells — look for the arsenic and uranium bedrock well probability map.
Treat that map as what it is: a probability for an area, not a measurement of your water. It tells you whether the question is worth putting on the list. Only a test tells you the answer.
And the reason it has to be a test rather than a judgment call: arsenic and uranium are odorless and tasteless. Water carrying them looks and tastes exactly like water that is not. There is no household observation that substitutes for a lab result here.
The geology section gets the attention, but it is not what we spend most of our time on. The everyday issues on wells around here are the ones a homeowner can usually see, smell, or feel:
This cluster is what our send-out chemistry panel is built around, and it is the bulk of the water work we actually do in Sherborn, Dover, Wayland, and Upton. It is also the part where you can usually tell something is going on before anyone tests anything — the geology items are the ones that give you nothing to notice.
Water treatment gets sold on worry, so we would rather write our own limits down than let them stay comfortably vague.
Being explicit, because this is exactly where a homeowner can end up assuming they are covered when they are not. We do not test for, and we do not arrange testing for, arsenic, uranium, radon, bacteria, PFAS, lead, or fluoride. None of those are on our on-site checks and none of them are on the panel we send out.
Those go to a MassDEP-certified lab, or start with your local board of health, which can tell you what your town requires and is often the fastest way to find out how testing is handled where you live. That relationship is a direct one between you and them — we are not in the middle of it.
Once there is a result, the mapping is fairly clean. Each of these is good at one thing and useless at the others, which is the whole reason the test comes first.
Arsenic is not one thing. Under NSF/ANSI 58, the arsenic claim is specifically for arsenic V. Arsenic III generally has to be oxidized first before the system can address it. Two wells can both read arsenic on a lab report and need two different specifications to actually deal with it.
Which is why this one in particular is not a buy-a-unit-off-a-shelf item. The lab result is what tells you which form you are dealing with, and the specification follows from that result rather than from the box copy.
Certification is contaminant-specific. The standard number by itself tells you nothing — two products can carry the same number and cover entirely different contaminants. Whatever your lab result names has to appear by name on that particular product listing. If a salesperson says it is NSF certified and stops there, the question has not been answered.
This one gets its own section because the coverage gap catches people out. Massachusetts sets a state drinking water standard for PFAS, and that standard applies to public water systems — it does not apply to private wells. A well owner is not covered by it and gets no results from it.
What MassDEP does say to private well owners is that they should test for PFAS roughly every ten years. That testing takes an independent certified lab, and as with everything else on this page, it is not something we perform or arrange.
The full version — the six compounds, the combined limit, what the standard covers, and what removes PFAS — is in our PFAS in Massachusetts drinking water guide.
Water quality is only half of what a well owner deals with. The other half is the machinery that gets the water into the house, and that is straightforward plumbing work.
We service and replace submersible and jet well pumps, pressure tanks, and pressure switches. Short cycling, pressure that swings, a pump that runs and runs, a tank that has lost its charge — those are the calls we take on wells, and they are diagnosable.
We do not drill wells. Deep-well drilling is its own trade with its own equipment, and we coordinate that with a well-driller partner rather than pretending it is in-house. More on the pump side is on our sump and well pump page.
Staining, hardness, pressure trouble, or a chemistry result you want read back to you in plain English — call and tell us what the water is doing. Mon–Sat 7am–5pm.