The use of single-pass filters, using medias such as granular activated carbon or ion exchange resin, for municipal water filtration to address specific contaminants of concern (COC) is increasing rapidly. As regulatory requirements tighten, COCs broaden in number and scope, and water sourcing narrows; single-pass media filters serve as a simple, useful, adaptive, and effective tool to aid water agencies in their mission for clean water. When designing single-pass media filters there is a tendency to focus heavily on the optimization of the media bed life. There is usually limited scrutiny on how the mechanical properties and physical system design can have considerable impact on the longevity of the asset and the overall cost of ownership. Critically, the opportunity cost of lower-priced and insufficiently designed capital equipment can be outweighed in the long run by a significant increase in operational costs over the life cycle of the equipment. There are four principal areas or tenets of design that have the biggest impact on the overall life-cycle cost for single-pass filters: Corrosion Management, Hydraulic Performance, Media Optimization, and Required Routine Operation and Maintenance. Proven history of single-pass media filter treatment systems that employ these designs around the four tenets, have 25 plus year life cycles. Understanding these design principles and applying them to the specific media, COC, and applications being considered will lead to an optimized system not only for the specific process but for overall life cycle costing. A case study will be used to illustrate these tenets in application. California Water Services has invested significant resources into single-pass filtration systems over the past 5 years in the Central Valley of California based on the 1,2,3-TCP COC. Their focus on optimized design has helped stabilize water rates for their consumers while still addressing effective treatment needs. These same engineering principles can be applied to any application for single-use medias.