8421.21.00.00 - For filtering or purifying water

This category, HTS 8421.21.00.00, specifically covers machinery and apparatus designed for the filtration or purification of water. This encompasses a wide range of devices, from simple household water filters to complex industrial water treatment systems, all sharing the primary function of removing impurities and contaminants from water. Examples include activated carbon filters, reverse osmosis units, sediment filters, and ion exchange systems when their sole or primary purpose is water treatment.

It is important to distinguish this classification from its siblings. HTS 8421.22.00.00 covers similar filtering and purifying apparatus, but exclusively for beverages other than water. Therefore, if a device filters or purifies wine, beer, or juice, it would fall under that heading. Similarly, HTS 8421.23.00.00 is dedicated to oil or fuel filters specifically for internal combustion engines, a distinct application from general water purification.

As this is a leaf node in the HTS structure, there are no further subcategories under 8421.21.00.00. Classification within this heading relies on the explicit and primary function of the apparatus being the filtration or purification of water, irrespective of the specific filtering medium or purification technology employed, as long as it is not exclusively or primarily for beverages other than water or for engine fuels.