UNSPSC 31161628: Square head bolt

A bolt with square shaped head.

UNSPSC 31161628 Square head bolt is a Commodity code that state and local governments buy as components within water infrastructure projects and equipment assemblies rather than as standalone procurement items. The recent opportunities record shows this code appearing in water treatment plant construction and water district equipment specifications, where square head bolts serve as fastening components in valve assemblies, basin modifications, filtration unit installation, and pump station work. State and local water utilities—city water departments, county water authorities, and regional water districts—source these bolts as part of larger capital projects or equipment procurements, typically through general construction contracts that specify component-level fastening requirements or through equipment RFQs where bolt specifications are embedded in assembly or valve drawings.

The code shows activity primarily in California and Georgia water infrastructure procurement as of mid-2026. The City of Lavonia, Georgia (under Fayette County) issued an IFB for Water Treatment Plant 2026 Improvements with a May 26, 2026 response deadline, encompassing plant modifications, raw water pump station work, and clearwell renovations where fastening components figure into the construction scope. The Eastern Municipal Water District (EMWD) in Riverside County, California issued an RFQ on March 17, 2026 (due March 20, 2026) for Lineseal XP 36" Butterfly Valves (Class 250B) with gaskets and bolt nut sets, indicating that square head bolts are procured as integral components of valve and equipment assemblies rather than as bulk commodity purchases. The code shows limited standalone procurement volume; bolts appear embedded in larger infrastructure or equipment contracts rather than as direct-buy line items.