Well water treatment cost varies dramatically based on your contaminants, from $300 for a basic sediment filter to $12,000 for multi-stage whole house systems. Equipment prices are just the starting point. Key Takeaways: Basic single-contaminant systems cost $300-$1,500, while multi-stage whole house systems run $3,000-$12,000 Installation adds 40-60% to equipment costs, with professional plumbing averaging … Read more