Northwest Pipe Company is the largest manufacturer of engineered welded steel pipe water systems in North America. Our manufa ... cturing facilities are strategically positioned to meet North America’s growing needs for water and wastewater infrastructure. Our solution-based products serve a wide range of markets including water transmission, plant piping, tunnels, and river crossings. Our prominent position is based on a widely-recognized reputation for quality, service, and manufacturing to meet performance expectations in all categories including highly-corrosive environments. To serve the recognized needs in water infrastructure, we manufacture large-diameter, high-pressure, engineered welded steel pipeline, as well as reinforced concrete pipe, Permalok® steel casing pipe, and T-Lock® and Arrow-Lock® protective lining systems. In addition to fabricating pipes for water transmission primarily related to drinking water systems, we also make products for hydroelectric power systems, wastewater systems, industrial plant piping systems, and certain structural applications. read more