When to Replace a Drain Line: The Signs That Repairs Are No Longer Enough The National Association of Home Inspectors identifies drain line condition as one of the top five plumbing concerns in residential inspections, particularly in homes built before 1970 with original clay tile or cast iron drainage systems. https://bloggingwebs.com/business/when-to-replace-a-drain-line-the-signs-that-repairs-are-no-longer-enough/