The United States Environmental Protection Agency recently issued a new MaximumContaminant Level (MCL) for arsenic in drinking water. The new MCL lowers theacceptable level of arsenic in drinking water from 50 parts per billion to 10 parts perbillion. Treatment technologies for arsenic removal are expensive to operate.Nontreatment options pose an alternative to treatment. Nontreatment is allowed undergovernment regulation. However, such options are limited by local hydrogeologicconditions. Many areas in Arizona have favorable conditions. Estimates for the capitalcosts for several nontreatment options were collected through surveys. In a comparison ofthe capital costs of nontreatment options to treatment, nontreatment was less than half thecost of treatment. Operating costs for nontreatment are also expected to be several timessmaller than for treatment. A comparison using annualized costs shows that nontreatmentcosts less than one fifth of treatment.