Water Collection Guide TL;DR A practical, step-by-step guide to residential and small-community water collection: what sources to use (rain, greywater, surface runoff), how to size tanks and filters, legal and safety considerations, basic system components, maintenance, and examples (DIY barrel, household cistern, small community system). Includes design calculations, common troubleshooting, cost ranges, and links to deeper resources on legal requirements, plumbing efficiency, automation, and moisture control. Introduction Water collection is the intentional capture, storage, and reuse of water from natural or household sources to reduce potable water demand, increase resilience during shortages, and provide an off-grid supply for irrigation, toilet flushing, laundry, and emergency use. With growing climate uncertainty and infrastructure stress, household- and community-scale water collection is an increasingly practical solution. This guide walks you through types of collection system...