Arsenic in well water: treatment at $300–$12,000 by system
Arsenic above the 10 microgram per liter federal limit takes dedicated treatment. Ohio's health department estimated in 2012 that a single-tap system costs $300–$1,500 and whole-house treatment $1,800–$12,000, depending on method. Softeners, carbon filters and sediment filters do not remove arsenic, and neither does boiling.
1,Key figures
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Cost by system
| System | Initial cost | Upkeep |
|---|---|---|
| Point of use, adsorptive media | $300–$700 | $300–$500 every 6 to 12 months |
| Point of use, reverse osmosis | $300–$1,500 | $100–$200 every 1 to 2 years |
| Point of use, distillation | $300–$1,200 | not given |
| Whole house, anion exchange | $1,800–$2,500 | $700–$900 every 8 to 10 years |
| Whole house, adsorptive media | $2,400–$4,500 | $700–$900 a year |
| Whole house, reverse osmosis | $5,000–$12,000 | $250–$500 every 1 to 2 years |
These are 2012 estimates and today's prices will be higher. We found no newer agency price list.
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Which arsenic you have matters
Arsenic occurs in two forms, As(III) and As(V). Ohio says anion exchange removes only As(V) and needs the water pre-oxidized first, and that whole-house reverse osmosis removes about 95 percent of As(V) but only 50 to 60 percent of As(III). Ask the lab to report the form, or plan for pre-oxidation.
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What does not work
Water softeners, activated carbon and sediment filters are not effective for arsenic, and boiling does not remove it. Single-tap reverse osmosis also sends 7 to 9 gallons to the drain for each gallon it treats.
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Common questions
Is treating one tap enough?
For drinking and cooking, Ohio lists point-of-use systems as an option. Whole-house treatment costs several times more.
Can a dry spell change arsenic levels?
It can. University of Minnesota Extension says air entering a well during drought may release naturally occurring contaminants such as arsenic, and advises testing regularly.
For the cost of a finished well in your state, see cost to drill a well.
Sources
- National Primary Drinking Water Regulations , U.S. EPA. Accessed November 9, 2026. Last updated August 31, 2026
- Arsenic Treatment and Removal for Private Water System Wells , Ohio Department of Health, Bureau of Environmental Health. Accessed November 9, 2026. June 2012 (cost estimates are 2012-era)
- Protecting your private well during drought , University of Minnesota Extension (Anne Nelson). Accessed November 9, 2026. Reviewed 2021
How these figures are built: methodology. Updated November 2026.