221320 — Sewage Treatment Facilities
Description
This industry comprises establishments primarily engaged in operating sewer systems or sewage treatment facilities that collect, treat, and dispose of waste.
Exclusions & Cross-References
- 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; and
- Cleaning and rodding sewers and catch basins--are classified in U.S. Industry 562998, All Other
- Miscellaneous Waste Management Services.
Overview Facts
| NAICS Code | 221320 |
|---|---|
| Industry Title | Sewage Treatment Facilities |
| SBA Size Standard | $35,000,000 |
| U.S. Establishments | 538 (Census CBP, 2023) |
| IRS PBA Code | 221300 (rolled-up match) |
| Sectors Hierarchy | Sector 22 → 221 → 2213 |
| Source / Verified | US Census 2022 NAICS Manual, Census CBP / 2026-06-28 |
Legacy SIC Concordance
Trace the historical mapping chain from the 1987 Standard Industrial Classification (SIC) to the modern 2022 NAICS code format.
- SIC 4952 - Sewerage Systems (via SIC1987:4952→NAICS1997:22132→2002:221320→2007:221320→2012:221320→2017:221320→2022:221320)
Suggested Product Service Codes (Advisory)
The following Product Service Codes (PSCs) are advisory suggestions aligned with this NAICS code. Note: NAICS and PSC codes map to different dimensions of procurement (industry vs. product/service). There is no official binding 1:1 crosswalk.
- PSC M1ND — OPERATION OF SEWAGE AND WASTE FACILITIES
Source: DoD DPCAP PSC Selection Tool (Ingested: 2026-06-29)
Related Resources & Compliance Guides
Further regulatory reference links for NAICS code 221320:
- Sector 22 Directory Hub — List of related industries in the Utilities sector.
- SIC ↔ NAICS Crosswalk Tool — Look up mappings between legacy SIC codes and modern classifications.
- SBA Size Standards Guide — Complete rules and averaging periods for small business classifications.
- Calculating Annual Receipts Guide — Detailed worked example of revenue calculation rules.
- IRS Principal Business Activity Guide — How NAICS codes map to corporate and entity tax filings.
Related Industries in 2213
Frequently Asked Questions (FAQ)
Is 221320 a valid 2022 NAICS code?
NAICS 221320 is 'Sewage Treatment Facilities', a 2022 U.S. national industry under Sector 22 (Utilities); the SBA small-business size standard is $35,000,000.
What is the SBA size standard for NAICS 221320?
The SBA small business size standard for NAICS 221320 is $35,000,000 (based on receipts).
What is the legacy SIC code mapping for 221320?
NAICS code 221320 maps to the legacy 1987 SIC codes: 4952 - Sewerage Systems.