Arsenic Treatment for Well Water in Derry, New Hampshire
New Hampshire sets its arsenic standard at half the federal limit, and for good reason. Here is what the number means, and what actually reduces it.
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Why This Is a New Hampshire Problem Specifically
It has no taste, no smell and no colour at any concentration you will encounter. Nothing about the water will tell you, which is the entire reason testing exists as a separate activity rather than something you do when the water seems off.
What the Numbers Mean
- New Hampshire standard: 5.0 ppb — the figure a private well result is sensibly measured against in this state.
- Roughly 25 to 30 percent of private wells exceed the state standard per NHDES estimates — which makes a positive result common rather than exotic.
- Your well is not your street — bedrock wells vary sharply over short distances, so the only number that describes your water is the one from your well.
How It Is Actually Reduced
There are two broad routes, and which is appropriate depends on the chemistry of your particular water rather than on preference. Point-of-use reverse osmosis treats water at a single tap — usually the kitchen — and is a well-established approach for drinking and cooking water. Whole-house treatment, typically some form of adsorptive media, treats everything entering the building. Iron content, pH and the form the arsenic takes all affect which works and how well, which is why a water test comes before a system rather than after it. NHDES publishes guidance on arsenic treatment for private wells that is written for homeowners.
The Questions That Separate a System From a Sales Pitch
- What is my actual arsenic level, in ppb? — treatment is designed against a number, not against a word like 'high'.
- What level is this system expected to achieve? — a specific target, in the same units.
- How will that be verified? — a retest after installation, not an assurance.
- What maintenance does it need, and how often? — media and membranes are consumables; a system nobody services stops performing quietly.
- Does this address anything else in my result? — and if not, say so plainly. A system that reduces arsenic and does nothing for radon is not a failure, but it should not be sold as comprehensive.
Arsenic Above 5.0 ppb in Derry?
Call (603) 704-2676 or send the result. Treatment gets designed against your actual number — and a retest afterwards is what proves it worked.
Arsenic Questions
Will a standard filter jug or fridge filter deal with arsenic?
Do not assume so. Filters sold for taste and odour are designed around chlorine and particulates, and arsenic reduction is a specific capability that a product either has been certified for or has not. The way to settle it is to look for certification against the relevant standard for arsenic reduction rather than reading the marketing on the box — and to remember that a device treating one tap does nothing about the water in the rest of the house. Where a health-based limit is exceeded, this is worth getting right rather than approximating.
If I install treatment, is the water then safe?
The honest framing is narrower than that, and worth insisting on. A properly specified and maintained system reduces arsenic to a measured level — below 5.0 ppb, for instance — and a retest after installation is what demonstrates it. That is a specific claim about a specific contaminant at a specific concentration. It is not a statement that the water is safe in general, because your result may contain other things the system was never designed to address, and because performance depends on maintenance continuing. Anyone answering this question with the word 'safe' and nothing else is not describing how treatment works.
Send the Test Result
No water this morning, a pump short-cycling, a pressure tank past its life, or a test result you do not know how to read — describe the system, result, and timing here.
Derry Resources for This Service
What Usually Turns Up Alongside It
Well work rarely stays in one lane. The pump raises the tank, the tank raises the pressure switch, and a transfer test raises everything that is dissolved in the water.