Germany urges households to brace for heavy rain and adopt rainwater collection

Authorities define heavy rain as 25 mm per hour or more than 35 mm in six hours, a level that can quickly overwhelm local drainage and cause flash floods even in residential areas without nearby streams. Saturated soil and blocked gutters increase the risk of water backing up into basements, light shafts and garages, potentially leading to structural damage and mold.

A 12‑step checklist advises residents to secure garden furniture, gather pots, clear gutters and surface drains, dismantle or tether loose outdoor items, perform a rapid roof‑gutter inspection, test the downspout with a hose, check and seal windows, and verify the operation of the backflow valve. Prompt action can limit water ingress and reduce repair costs.

Separately, rainwater collectors installed in roof downspouts divert clean roof runoff into storage tanks instead of the sewage system. Built‑in filters remove leaves and debris, lowering treatment expenses for wastewater utilities and providing usable water for household or garden purposes. Proper sizing, slope and connection of the collector are essential to avoid backflow and maintain water quality.