NAICS Code 237110 — Water and Sewer Line and Related Structures Construction

National Industry in the official 2022 North American Industry Classification System (U.S. Census Bureau). It is the only national industry under 23711 (Water and Sewer Line and Related Structures Construction).

Code	237110
Title	Water and Sewer Line and Related Structures Construction
Level	National Industry (6-digit)
Edition	NAICS 2022 edition
SBA size standard	$45 million in average annual receipts

Official definition (2022 NAICS)

This industry comprises establishments primarily engaged in the construction of water and sewer lines, mains, pumping stations, treatment plants, and storage tanks. The work performed may include new work, reconstruction, rehabilitation, and repairs. Specialty trade contractors are included in this industry if they are engaged in activities primarily related to water, sewer line, and related structures construction. All structures (including buildings) that are integral parts of water and sewer networks (e.g., storage tanks, pumping stations, water treatment plants, and sewage treatment plants) are included in this industry.

Illustrative Examples:

Distribution line, sewer and water, construction

Sewer main, pipe and connection, construction

Fire hydrant installation

Storm sewer construction

Irrigation systems construction

Water main and line construction

Sewage disposal plant construction

Water treatment plant construction

Pumping station, water and sewage system, construction

Water system storage tank and tower construction

Reservoir construction

Water well drilling, digging, boring, or sinking (except water intake wells in oil and gas fields)

Is a business under 237110 "small"?

Under the SBA size standards (13 CFR 121.201, effective March 17, 2023), a business classified in NAICS 237110 qualifies as a small business if it does not exceed $45 million in average annual receipts. Small-business status determines eligibility for federal set-aside contracts, SAM.gov certifications and SBA loan programs — receipts are averaged over the latest 5 fiscal years.

Where 237110 sits in the hierarchy

Level	Code	Title
Sector	23	Construction
Subsector	237	Heavy and Civil Engineering Construction
Industry Group	2371	Utility System Construction
NAICS Industry	23711	Water and Sewer Line and Related Structures Construction
National Industry	237110	Water and Sewer Line and Related Structures Construction

Related SIC codes

Via the official U.S. Census concordance (1987 SIC ↔ NAICS), shown only where the industry definition is unchanged in NAICS 2022.

SIC code	Title
1623	Water, Sewer, Pipeline, and Communications and Power Line Construction
1629	Heavy Construction, Not Elsewhere Classified
1781	Water Well Drilling
8741	Management Services

Data: official 2022 NAICS structure, descriptions and Census concordances, U.S. Census Bureau — U.S. government works in the public domain (17 U.S.C. §105). Suggested reference, not an official determination.