2022 NAICS national industry in sector 22 Utilities
221310 Water Supply and Irrigation Systems
NAICS 221310 is the US industry code for water supply and irrigation systems. It covers establishments primarily engaged in operating water treatment plants and/or operating water supply systems.
- Code
- 221310 (2022 NAICS)
- Title
- Water Supply and Irrigation Systems
- Part of
- Water, Sewage and Other Systems
- SBA small business limit
- Average annual receipts up to $41 million
- Closest UK SIC
- 36000 (details)
Changes coming. The NAICS 2027 revision applies to data from 1 January 2027, and SBA proposed new size standards on 20 August 2026. The values on this page are the ones in force today; we update this page when the official files change.
Official definition
This industry comprises establishments primarily engaged in operating water treatment plants and/or operating water supply systems. The water supply system may include pumping stations, aqueducts, and/or distribution mains. The water may be used for drinking, irrigation, or other uses.
When to use a different code
Census classifies these close-sounding activities somewhere else. Businesses mainly engaged in:
- Establishments primarily engaged in irrigation project construction (except lawn) are classified in Industry 237110, Water and Sewer Line and Related Structures Construction.
- Establishments primarily engaged in installing lawn sprinkler systems are classified in Industry 238220, Plumbing, Heating, and Air-Conditioning Contractors.
- Establishments primarily engaged in lawn irrigation services are classified in Industry 561730, Landscaping Services.
- Establishments primarily engaged in retailing bottled water are classified in U.S. Industry 445298, All Other Specialty Food Retailers.
- Government establishments primarily engaged in administering irrigation districts are classified in Industry 926130, Regulation and Administration of Communications, Electric, Gas, and Other Utilities.
Activities listed under 221310
The Census index assigns these 10 activities to this code. If your business matches one, this is your code.
- Canal, irrigation
- Filtration plant, water
- Impounding reservoirs, irrigation
- Irrigation system operation
- Water distribution (except irrigation)
- Water distribution for irrigation
- Water filtration plant operation
- Water supply systems
- Water treatment and distribution
- Water treatment plants
SBA size standard for 221310
To count as a small business for SBA loans and federal contracts under NAICS 221310, your business (including affiliates) must not exceed $41 million in average annual receipts. Check your business.
Source: SBA table of size standards, effective March 17, 2023.
Closest UK SIC 2007 codes
There is no official one-to-one link between NAICS and UK SIC. These codes share the same international class (ISIC Rev. 4: 3600, 4930), so treat them as a starting point and check the definition.
Built from Census concordances 2022→2017 NAICS and 2017 NAICS→ISIC Rev. 4.
Similar codes to compare
Data last changed November 14, 2026. How this page is built.