A San Jose Homeowner’s Guide to Protecting Property & Health Plumbing leaks rarely stay simple. What begins as a slow drip behind drywall or under a sink can escalate into structural damage, indoor air contamination, and costly remediation. In San Jose , where many homes include aging copper lines, slab foundations, and concealed plumbing systems, hidden leaks frequently go unnoticed — until mold becomes a serious problem. Understanding how mold develops from plumbing failure