Each state publishes its own HQ100/HQ200 (100/200-year flood) hazard zones independently — there's no single federal source, so coverage and detail vary by state. Toggle layers in the control at the top right. Some services could not be verified with a direct test call from this environment and are included based on their official capabilities documentation.
Sources: state environmental/water authorities of Rhineland-Palatinate, North Rhine-Westphalia, Lower Saxony, Bavaria, Hesse, Baden-Württemberg, Saxony, Saxony-Anhalt, Thuringia, Brandenburg, Mecklenburg-Vorpommern, Schleswig-Holstein, Saarland, Berlin, Bremen and Hamburg. Live WMS layers, rendered directly — not reinterpreted.