2022 NAICS national industry in sector 22 Utilities
221320 Sewage Treatment Facilities
NAICS 221320 is the US industry code for sewage treatment facilities. It covers establishments primarily engaged in operating sewer systems or sewage treatment facilities that collect, treat, and dispose of waste.
- Code
- 221320 (2022 NAICS)
- Title
- Sewage Treatment Facilities
- Part of
- Water, Sewage and Other Systems
- SBA small business limit
- Average annual receipts up to $35 million
- Closest UK SIC
- 37000 (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 sewer systems or sewage treatment facilities that collect, treat, and dispose of waste.
When to use a different code
Census classifies these close-sounding activities somewhere else. Businesses mainly engaged in:
- Operating waste treatment or disposal facilities (except sewer systems or sewage treatment facilities) are classified in Industry 56221, Waste Treatment and Disposal.
- Operating water treatment plants and/or operating water supply systems are classified in Industry 221310, Water Supply and Irrigation Systems.
- Pumping (i.e., cleaning) cesspools, portable toilets, and septic tanks or renting portable toilets are classified in U.S. Industry 562991, Septic Tank and Related Services.
- Cleaning and rodding sewers and catch basins are classified in U.S. Industry 562998, All Other Miscellaneous Waste Management Services.
Activities listed under 221320
The Census index assigns these 5 activities to this code. If your business matches one, this is your code.
- Collection, treatment, and disposal of waste through a sewer system
- Sewage disposal plants
- Sewage treatment plants or facilities
- Sewer systems
- Waste collection, treatment, and disposal through a sewer system
SBA size standard for 221320
To count as a small business for SBA loans and federal contracts under NAICS 221320, your business (including affiliates) must not exceed $35 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: 3700), 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.