Plumbing engineers and designers have been talking about it for what seems like forever. Plumbing installers have been looking into ways to become more efficient. Plumbing manufacturers have been collecting the data to better size their equipment. And plumbing inspectors and plan reviewers have been acutely aware of the need for change for a long time.

The primary cost savings are associated with reduced diameter water service entrances, interior cold water mains/branches, interior hot water mains/branches, fittings, labor, and appurtenances.