Point-of-use/point-of-entry treatment can provide an affordable means for rural residents on private wells to remedy groundwater contamination. Cooperation among homeowners was hypothesized to be a means of further reducing treatment costs due to quantity discounts and avoidance of dealer mark-ups. Data obtained through a mail survey of water treatment firms was used to test this hypothesis. Individual and group purchase, installation and maintenance costs and manufacturer and dealer costs were compared using analysis of variance. Results indicate a cooperative treatment approach may provide benefits due to quantity discounts but little potential exists for savings via direct manufacturer purchase.