North American Product Classification System (NAPCS) Canada 2022 Version 1.0
- 623 - Civil engineering works
- 62352 - Sewage engineering works
- 623521 - Sewage treatment plants
- 6235211 - Sewage and wastewater treatment plants
- 623522 - Sewage collection and disposal engineering works
- 6235221 - Sewage collection and disposal engineering works
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