The simplest decision rule: test your water first, target the contaminants you actually have, then pick the technology that addresses those without unnecessarily stripping the water bare. • Taste + mineral-friendly: certified activated carbon • Clarity + cyst protection + mineral retention: UF plus carbon • Maximum contaminant reduction for problem water: RO + remineralization If you're unsure, start with a certified carbon filter that matches your lifestyle, then upgrade based on your water test results or your provider's water quality report.