Portland homes built before 1940 — Irvington, Ladd's Addition, Eastmoreland, inner SE — were almost all plumbed with galvanized steel. It corrodes from the inside out, and after 80–90 years, the narrowing is severe enough to drop pressure throughout the house. Homes built between 1978 and 1995 have a different problem: polybutylene pipe (sold as Quest, Poly-B, or Vanguard), which most insurers now flag or exclude from coverage.
If you're planning to sell or refinance in the next few years, old supply lines are often the single item that gives buyers leverage at the negotiating table — or kills the deal. Portland home inspectors flag galvanized and polybutylene on nearly every report in these neighborhoods. A completed repipe with a closed city permit removes that line item from the inspection report before any buyer sees it.