Residential hazard law is not a safety regime. It is a disclosure and notice regime, and almost everything confusing about lead and mold liability follows from that one design choice. This article explains why federal law never required anyone to remove lead paint from a house, what the disclosure rule actually obliges a seller or landlord to do, and why the renovation rules — not the disclosure rules — generate most of the enforcement. It then turns to mold, which has the opposite structure: essentially no federal regulation, no numeric standard, and therefore a claim built entirely on water intrusion, notice, and habitability. It covers how insurance policies were rewritten to exclude exactly this loss, how the fair housing statutes turn a landlord's risk-avoidance instinct into a violation, and what actually proves or defeats a residential hazard case.