Off-Grid Water Filtration: Whole House Systems Whole-house off-grid water filtration provides treated water at every tap, protecting health, extending appliance life, and preventing scale and staining in plumbing. An off-grid water filter needs to match the home's source—well, raincatchment, or surface water—while fitting peak flow, storage, and the available power budget. This guide explains how to choose, size, power, install, and maintain a whole-house off-grid water filter so a DIY self-builder or tiny-homestead owner can make practical, cost-aware decisions. TL;DR: - Pick treatments based on tests: test water first (microbial, nitrates, hardness); private wells commonly show bacteria and nitrates, raincatchment often has particulates — test at least annually. - Design for peak flow: typical household peak flow 8–12 gpm; match filter housing and cartridge size (10"–20", 1"–2" ports) and include settling/storage for rainwater. - Plan low-energy operation: prefer DC or low-wattage pu...