Water quality is a legitimate concern for homeowners across New Hampshire, and one of the most frequently overlooked issues is radon in drinking water. While radon in indoor air gets significant attention — particularly in a state where geologic conditions produce some of the highest radon levels in the country — radon in water is a separate concern with its own testing requirements and treatment approaches.
This guide covers the basics of water-borne radon, how to have it tested, and what treatment options exist, alongside a broader overview of how to find reliable water treatment expertise in the state.
Radon in Water: Why New Hampshire Is Particularly Affected
Radon is a naturally occurring radioactive gas produced by the decay of uranium, which is present in New Hampshire’s granite bedrock in relatively high concentrations. As water percolates through rock, it picks up dissolved radon gas. Private wells drilled into bedrock — the most common well type in New Hampshire — have a much higher probability of water-borne radon than drilled wells in sedimentary geology or surface water sources.
Municipal water from surface water sources (lakes, rivers) contains very little radon because the gas escapes to the air during storage and treatment. Municipal water from groundwater sources is more likely to contain radon, though municipal systems are required to test for it and treat it if levels exceed EPA guidance.
The health concern with water-borne radon is twofold. First, radon-contaminated water used for showering and other activities that aerosolize the water (dishwashers, washing machines) releases radon into indoor air, contributing to elevated indoor air radon levels. Second, ingesting water with dissolved radon is associated with a small but measurable increase in stomach cancer risk at elevated concentrations.
If you’re concerned about your water’s radon content and want to safeguard your water from radon, the process starts with a test from a certified laboratory. New Hampshire has specific guidance on radon in water testing, and the Department of Environmental Services maintains a list of certified labs.
Treatment Options for Water-Borne Radon
Unlike air-borne radon (where mitigation involves sub-slab depressurization and sealing), water-borne radon is typically addressed through one of two primary treatment methods:
Aeration. Aeration systems introduce air into the water and allow radon gas to escape before the water enters the distribution system. Point-of-entry aeration systems treat all water entering the home and are effective at removing 95-99% of dissolved radon. They require a housing space (often in the basement or utility room) and produce some noise during the aeration process.
Granular activated carbon (GAC). GAC filters adsorb radon onto the carbon media, effectively removing it from the water. GAC systems are simpler and quieter than aeration systems but have a consideration: the carbon media becomes radioactive as it traps radon and its decay products. This affects how the filter media must be handled at the end of its service life, and some jurisdictions have specific disposal requirements.
For homes with elevated water-borne radon, professional evaluation is recommended to determine which treatment approach is more appropriate for the specific situation, home layout, and radon concentration level.
Finding Reliable Water Treatment Expertise in New Hampshire
New Hampshire has a range of water treatment companies, from national chains to local specialists. The advantages of working with a local provider are meaningful: familiarity with regional water quality issues, knowledge of what’s common in specific areas, and the ability to provide ongoing service and maintenance rather than leaving you to manage it remotely.
Absolute Water System is an example of a New Hampshire-based water treatment specialist with expertise in the specific contaminants common in the region — radon, arsenic, hardness, iron, and bacterial issues that private well owners across the state deal with regularly. Local specialists of this type have typically tested hundreds of wells in the area and have developed efficient approaches to the common problems they see repeatedly.
If you’re not sure where to start, you can find them in New Hampshire to schedule a consultation. Many water treatment companies offer free water testing or consultations as an entry point to understanding your home’s specific needs before committing to any treatment system.
Questions to Ask When Evaluating a Water Treatment Company
Whether you’re getting quotes for a water softener, a whole-house filtration system, or radon treatment, a few questions will help you evaluate whether you’re working with a knowledgeable provider:
Do you test water before recommending treatment? Any reputable provider starts with a comprehensive water test rather than leading with a treatment recommendation. A company that wants to install a softener before they’ve tested your water isn’t providing water quality service — they’re selling products.
What’s included in the water test, and is it performed by a certified lab? Comprehensive testing through a certified laboratory is more reliable than in-home test kits for contaminants like radon and arsenic that require careful sample handling.
Can you explain why the recommended treatment is appropriate for my specific test results? A knowledgeable provider should be able to walk you through the logic of their recommendation in plain language, connecting specific contaminants in your water to specific treatment technologies.
What maintenance does the system require, and what does that look like over time? Filter replacements, lamp replacements for UV systems, resin service for softeners — understanding the ongoing commitment is important before purchase.
Are you licensed and insured for plumbing work in New Hampshire? Treatment system installation typically involves modifications to your home’s plumbing. Verify that the company is appropriately licensed.
The Importance of Ongoing Testing
Installing a treatment system is the beginning of water quality management, not the end. Water quality from private wells can change over time — in response to seasonal variation, changes in local geology, nearby land use changes, or degradation of well components. Annual or biennial testing ensures that your treatment system is still matched to the water it’s treating.
For homes with radon treatment systems, periodic testing confirms that the system is performing as intended. Aeration systems require maintenance and filter media replacement; testing verifies that radon removal efficiency is maintained over time.
New Hampshire homeowners who treat water quality management as an ongoing part of home maintenance — rather than a one-time installation — reliably get better long-term results. Know what’s in your water, treat it appropriately, and verify that the treatment is working. That’s the whole process.
