U.S. imports of Water Filtering & Purifying Machinery and Apparatus (HS 842121) totaled $170.1M in August 2026, imported from 65 countries.
Importers of Water Filtering & Purifying Machinery and Apparatus paid $15.8M in duties in August 2026, an average duty rate of 9.35% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule.
Last updated: August 2026 dataWater filtration and purification equipment — from municipal treatment systems and industrial process water units to point-of-entry commercial systems — enters under the single US line 8421210000. Canada and Mexico are the leading import sources, consistent with deep North American supply-chain integration in water treatment infrastructure, with China, South Korea, and Germany also significant. This heading is distinct from apparatus that purifies water by UV or chemical dosing alone; the classification turns on whether the equipment mechanically filters or physically purifies the water stream. Importers should also be aware that certain water treatment systems may require EPA or state-level regulatory review depending on their intended application.
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5.4K import shipments a month
Yes — reverse osmosis systems that filter or purify water by forcing it through a semi-permeable membrane are generally classified under 8421210000 as water filtering or purifying machinery. The membrane-based separation is considered a filtering/purifying process for HTS purposes. However, if the RO unit is integrated into a larger system with a primary function other than water purification, the classification of the complete system may differ, and a principal-function analysis would apply.
Heading 842121 is specifically limited to water filtering and purifying machinery. Equipment designed to filter or purify other liquids — oils, beverages, chemicals — classifies under different subheadings within heading 8421 (such as 842129 for other liquid filtering/purifying apparatus). The nature of the liquid the equipment is designed to process is the controlling distinction, not the filtration technology used.
Subheading 4 of 12 in heading 8421
Subheading 842121 · $170.1M of $1.4B
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Imports for consumption | Average duty rate | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 8421210000 | Water Filtering or Purifying Machinery & Apparatus | $169.0M | 9.35% | 68.92% | $15.8M |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 8421210000 | Water Filtering or Purifying Machinery & Apparatus | $90.0M |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
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ImportsExports
Imports
$170.1MYoY · free account
Exports
$90.0MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $1.9B of Water Filtering & Purifying Machinery and Apparatus and exported $1.3B.
Imports · August 2026
origin
China pays 29.5% duty; Canada 0.4%.
customs district
destination
entry
rate provision · imports
30.7% enters free of duty; duty collected equals 9.35% of imports for consumption.
Through August 2026. Source: U.S. Census Bureau.