Product classification

HS code for Water treatment machine: 8421.21

Machinery, for filtering or purifying water.

Classification of water treatment machine under HS 8421.21

Water treatment machines are classified under HS code 842121. This classification covers a broad spectrum of machinery used to alter the quality of water to make it potable, usable for industrial processes, or safe for discharge into the environment. The logic for this classification follows the functional description of heading 8421, which includes filtering and purifying machinery and apparatus for liquids. A "water treatment machine" is essentially a purifier or filter on a larger or more specialized scale. This includes systems that remove physical debris, chemical contaminants, or biological pathogens. The classification is applicable to both self-contained units and large-scale modular systems, provided they function as a mechanical or physical treatment apparatus. Under the General Rules for the Interpretation of the Harmonized System (GRI), specifically GRI 1, the specific mention of "filtering or purifying water" in subheading 842121 makes it the mandatory choice for these machines. This remains true even if the machine incorporates advanced technology like ozone generators or sophisticated electronic monitoring, as the primary objective is the purification of the water stream.

Covers
  • Industrial water softening plants
  • Desalination machines (Reverse Osmosis)
  • Deionization systems for ultrapure water
  • Sedimentation and clarification systems
  • Electrodeionization (EDI) units
  • Ozone water treatment modules
Also under 8421.21
  • Culligan water softeners
  • Brita water filters
  • GE Water & Process Technologies RO systems
  • Siemens Water Technologies
  • Pentair water filtration systems

Codes often confused with 8421.21

Common mistake. Water treatment machines are sometimes misclassified under HS code 841989, which covers machinery for the treatment of materials by a process involving a change of temperature. While some treatment systems use heat, the primary function of purification usually dictates 842121. Another common error is using 842139, which is for filtering or purifying gases. Importers must ensure they distinguish between liquid (84212) and gas (84213) filtration to avoid customs delays and incorrect duty payments.

8419.89Machinery, plant and laboratory equipment; for treating materials by change of temperature, other than for making hot drinks or cooking or heating food8421.39Machinery; for filtering or purifying gases, other than intake air filters, catalytic converters or particulate filters for internal combustion engines

Top exporters and importers of HS 842121 (the code used for water treatment machine), 2025

In 2025, the largest exporter of HS 842121 (the code used for water treatment machine) in UN Comtrade data was China, with 17% of world exports; the largest importer in UN Comtrade data was the United States, with 16% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.

Figures cover everything classified under HS 842121, not only water treatment machine.

Top exporters 2025 · share of world exports

  1. 1 China $2.0B
  2. 2 Germany $1.6B
  3. 3 United States $1.3B

World total: $12.3B Reported figures on UN Comtrade ↗

Top importers 2025 · share of world imports

  1. 1 United States $1.9B
  2. 2 Germany $652M
  3. 3 Canada $448M

World total: $11.9B Reported figures on UN Comtrade ↗

How these figures are built

109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).

Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.

Brazil NCM code for water treatment machine

Brazil classifies water treatment machine under NCM 8421.21.00: HS 8421.21 with 00 added.

Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.

Questions about water treatment machine

What is the HS code for Water treatment machine?

The HS code for Water treatment machine is 842121 (Machinery; for filtering or purifying water). The HS code for water treatment machines is 842121, the same code used for water purifiers and filtering apparatus.

How do I classify Water treatment machine for customs?

Water treatment machine is classified under HS code 842121 — Machinery; for filtering or purifying water. This is a 6-digit subheading level code.

Are industrial desalination plants under this code?

Yes, industrial-scale desalination plants that use membrane filtration or reverse osmosis are classified under 842121 as water purifying machinery.

Which countries are the top exporters of water treatment machine (HS 842121)?

In 2025, the top exporters of HS 842121 (the code used for water treatment machine) in UN Comtrade data were China ($2.0B, 17% of world exports), Germany ($1.6B) and the United States ($1.3B). World exports came to about $12.3B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

Which countries are the top importers of water treatment machine (HS 842121)?

In 2025, the top importers of HS 842121 (the code used for water treatment machine) in UN Comtrade data were the United States ($1.9B, 16% of world imports), Germany ($652M) and Canada ($448M). World imports came to about $11.9B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

Is the HS code for Water treatment machine the same in all countries?

The base HS code 842121 for Water treatment machine is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.

What is the NCM code for water treatment machine in Brazil?

In Brazil, water treatment machine (HS 842121) is classified under NCM 8421.21.00.