NAICS 237990

Overview

The North American Industry Classification System is the federal standard for grouping business establishments so agencies can collect, analyze, and publish economic statistics consistently across the United States, Canada, and Mexico. Created under the Office of Management and Budget and adopted in 1997 to replace SIC, NAICS is production‑oriented; the current statistical vintage is 2022. ¹

NAICS 237990 covers “Other Heavy and Civil Engineering Construction.” Per the NAICS manual, it includes heavy/civil projects other than highway, street, bridge, and distribution‑line work. Typical activity includes new construction, reconstruction, rehabilitation, and repairs, and also specialty trade work specific to heavy/civil projects (e.g., dredging, microtunneling). Projects commonly involve water resources (dredging, drainage), marine facilities, and open‑space improvements such as parks and trails. ²

What this NAICS covers

• Dams, flood control works, and hydroelectric generating stations. ²
• Marine and port facilities, docks, and related waterfront construction. ²
• Dredging and waterway/channel construction or improvement. ²
• Tunnels, subways, microtunneling, and underwater trenching. ²
• Railroad and mass transit line construction. ²
• Parks, trails, and recreational open‑space improvements. ²
• Horizontal drilling for cable, pipeline, or sewer installation (heavy/civil context). ²

Related NAICS and PSC codes

Key exclusions (classify elsewhere)

• Water mains, sewers, and related structures belong in 237110. ²
• Oil and gas pipelines and related structures fall under 237120. ²
• Power and communication transmission lines and related structures are in 237130. ²
• Highways, streets, and bridges are covered by 237310. ²
• Trenching (except underwater) and removal of dams/dikes are handled in 238910. ²
• Pipeline inspection services are classified in 541990. ²

Small business size standard (SBA)

For NAICS 237990, SBA’s small business size standard is $45.0 million in average annual receipts; a special standard of $37.0 million applies to Dredging and Surface Cleanup Activities (effective March 17, 2023). Always consult the current SBA table for updates. ³

Frequently asked questions

• What types of projects typically use NAICS 237990?

  Typical projects include dams and levees; dredging and channel improvements; ports and marine structures; tunnels and subways; rail and mass transit lines; and park/trail/open‑space improvements. It also covers specialty trades integral to heavy/civil projects (e.g., microtunneling, underwater trenching) when performed as part of such work. ²

• How does 237990 differ from 237310 and utility system construction?

  237990 excludes highways, streets, and bridges (see 237310) and most distribution‑line work. Utility systems are classified separately: water/sewer in 237110, oil/gas pipelines in 237120, and power/communication lines in 237130. ²

• Are design‑build firms and specialty trade contractors included in 237990?

  Yes. Establishments responsible for heavy/civil projects (including design‑build) and specialty trade contractors performing activities specific to heavy/civil construction—such as dredging or microtunneling—are included. Specialty trades primarily serving building construction are classified elsewhere. ²

• What is the current NAICS vintage used for federal economic statistics?

  Federal statistical programs use the 2022 NAICS vintage going forward; the Census Bureau’s Economic Census and related tools reflect the 2022 structure and provide guidance for data users transitioning from prior vintages. Always verify program‑specific implementation timing. ¹

• Did the 2022 revision change the definition of 237990?

  The 2022 NAICS materials do not publish a specific change note for 237990 relative to 2017. Users should review the 2022 code lists and concordances before reclassifying historical work. Not specified by official sources. ¹

Useful resources

• G2X — NAICS 237990 overview: https://app.g2xchange.com/naics/237990
• U.S. Census Bureau — NAICS Codes & Understanding Industry Classification Systems (2022). ¹
• U.S. Census Bureau — 2017 NAICS Manual (industry descriptions for 237990 and cross‑references). ²
• SBA — Table of size standards (effective March 17, 2023). ³
• GSA — Product and Service Code (PSC) Manual (FY 2025 edition). ⁴

References

1. U.S. Census Bureau. Economic Census: NAICS Codes & Understanding Industry Classification Systems (2022 Guidance for Data Users). https://www.census.gov/programs-surveys/economic-census/year/2022/technical-documentation/code-lists/understanding-naics-redirect.html
2. U.S. Census Bureau. North American Industry Classification System: United States, 2017 (NAICS Manual). https://www2.census.gov/library/reference/naics/publications/2017-NAICS-Manual.pdf
3. U.S. Small Business Administration. Table of size standards. https://www.sba.gov/document/support--table-size-standards
4. U.S. General Services Administration. Product and Service Codes (PSC) Manual, Fiscal Year 2025 Edition. https://www.acquisition.gov/sites/default/files/manual/PSC%20Manual%20April%202025.pdf