Why do quotes for the same problem vary so much?

Because the same contaminant at different concentrations, in different background chemistry, at different household flow rates, is not the same job. Iron in the water can foul arsenic media, low pH can call for pre-treatment, and a four-bath house needs more capacity than a camp. Two honest quotes can differ for real reasons, which is why quotes should follow lab numbers.

Is an under-sink unit always cheaper than whole-house?

Almost always upfront: cited reverse osmosis ranges start at $150 in equipment while whole-house arsenic systems start around $2,000. But point of use only protects one tap. Radon and bacteria involve every fixture, so cheap-at-one-tap is not an option for them. The right comparison is cost against the exposure the lab report shows.

What should I budget per year after installation?

From the cited sources: $200 to $300 for arsenic media replacement, about $500 for uranium anion exchange upkeep, $50 to $150 for a UV lamp, plus reverse osmosis filter sets and softener salt. Add one verification lab test to confirm the system is doing its job. Skipped maintenance is the most common way a good system quietly stops working.

Is there any financial help for Maine well owners?

Two programs are worth checking. MaineHousing runs a Well Water Abatement program for eligible homeowners; funding comes and goes, so check its current status. Maine DEP offers free PFAS testing near licensed sludge and septage sites and funds filtration where contamination is linked to them. Both links are in the guide above.

What well water treatment costs in Maine

Price ranges beat price mysteries. A Maine well owner staring at an arsenic or radon exceedance deserves real numbers before the first sales call, so this page collects the published cost ranges for every common treatment system, each with its source, plus the yearly maintenance line items that quotes tend to whisper. None of these are our prices: Down East Well Water sells nothing and installs nothing. We connect owners with independent local professionals, and the referral fee the professional pays never touches your quote, as laid out on the how we make money page.

One framing rule before the table: cost only means something next to a lab number. A $6,000 radon system is the wrong buy at 2,000 pCi/L and a sound one at 9,000. If you have not tested, start at the testing page; if you have a report you cannot read, the results explainer comes first.

Cost summary, cited ranges

Published national and regional figures, not quotes. Sources are linked in each section below.

System	Upfront	Ongoing
Reverse osmosis, under sink	$150 to $1,300 plus $150 to $300 install	Filter and membrane sets
Whole-house arsenic media	$2,000 to $3,000 installed; $1,000 to $5,000 spread	$200 to $300 per year
Radon aeration	$6,000 to $8,000 regional; $4,000 to $5,000 national	Fan and jet upkeep
Uranium anion exchange	About $3,000	About $500 per year
Iron and manganese air injection	$1,500 to $4,000	Periodic media
UV disinfection	$700 to $2,500 installed	Lamp $50 to $150 per year

Reverse osmosis: $150 to $1,300 plus install

The under-sink workhorse for drinking-water contaminants: designed to reduce arsenic, uranium, nitrate, and PFAS at one tap. This Old House puts point-of-use units at $150 to $1,300 in equipment plus $150 to $300 for professional installation. The wide equipment range reflects membrane quality, number of stages, and tank size. Ongoing cost is filter and membrane replacement on the maker's schedule, and skipping it is how a unit degrades without anyone noticing. Where reverse osmosis fits in the arsenic decision is covered on the arsenic treatment page.

Whole-house arsenic media: $2,000 to $3,000 installed

Point-of-entry adsorption systems treat every tap in the house. An EPA-hosted guidance sheet puts typical installed cost at $2,000 to $3,000 with media replacement running $200 to $300 per year. Broader industry figures stretch the range to $1,000 to $5,000 depending on capacity and site work. The media bed is the recurring cost that matters: it exhausts on a schedule set by your arsenic level and water use, not by the calendar.

Radon aeration: $6,000 to $8,000 in this region

The big-ticket item. Aeration systems strip radon gas from incoming water and vent it above the roofline, and regional installer data for Maine, New Hampshire, and Massachusetts puts installed cost at $6,000 to $8,000, against a national figure of $4,000 to $5,000. The regional premium is real: northern New England installs deal with basements, freeze protection, and venting runs that flatter national averages do not. Ongoing costs are modest, mostly the blower and periodic jet or diffuser cleaning. Whether aeration or carbon fits your number is covered on the radon in water page.

Uranium anion exchange: about $3,000

For whole-house uranium reduction, anion exchange is the standard approach, and the National Ground Water Association puts a typical system near $3,000 with roughly $500 per year in operating cost. Households treating uranium only at the drinking tap often use reverse osmosis instead, at the point-of-use prices above.

Iron and manganese air injection: $1,500 to $4,000

The everyday Maine complaint, orange stains and black flecks, is usually solved with an air-injection oxidizing filter. Industry pricing puts these at $1,500 to $4,000 installed, consistent with HomeGuide's well filtration figures. Media life depends on iron load. The diagnosis path from stain color to test to system is on the iron and manganese page.

UV disinfection: $700 to $2,500 installed

For recurring bacteria hits, UV systems run $700 to $2,500 installed per HomeGuide, with Modernize reporting similar figures, plus a replacement lamp at $50 to $150 per year. The lamp swap is annual and non-optional: the lamp dims before it dies. Sediment or iron in the water can shield microbes from the light, so UV sometimes needs prefiltration, one of the classic cost adders below.

What pushes a quote up or down

Background chemistry. Iron and manganese foul arsenic media and shield bacteria from UV; low pH corrodes; hardness scales membranes. Pre-treatment stages are the most common surprise line on a quote, and a full lab panel predicts them.
Concentration. Higher numbers can mean larger media beds, more stages, or aeration instead of carbon. The gap between 12 ug/L and 80 ug/L of arsenic is a design difference, not a markup.
Point of use versus point of entry. One tap or every tap. Contaminants you drink can sometimes be handled at one tap; contaminants you breathe or bathe in cannot.
Household demand. Bathrooms, occupants, and peak flow size the equipment.
Site conditions. Tight mechanical rooms, long venting runs for aeration, freeze protection, and drain access all add labor.
Competition. Two or three quotes against the same lab report is the honest way to find the local market price.

One more resource before you spend: MaineHousing operates a Well Water Abatement program for eligible homeowners; check its current funding status. And if your well sits near a licensed sludge or septage site, Maine's PFAS program offers free testing and funds filtration where contamination is linked, detailed on the PFAS page.

Get a real number for your water

Ranges end where your lab report begins. Tell us your town and what the test found, and we connect you free with an independent local professional who can quote a sized system against your actual numbers.