8421.99.01.40 - Parts of machinery and apparatus for filtering or purifying water

This HTS category, 8421.99.01.40, specifically covers parts and accessories designed for machinery and apparatus used in the filtration or purification of water. This encompasses a wide array of components that contribute to the operational function of water treatment systems. Examples include replacement filters, membranes, housings for filter cartridges, pumps specifically designed for water purification units, control valves, and any other discrete parts that are integral to the process of removing impurities or contaminants from water, whether for residential, commercial, or industrial applications.

The distinction of this subcategory lies in its exclusive focus on water filtration and purification. While the broader heading 8421.99 covers "Other" parts for filtering or purifying machinery and apparatus for liquids or gases, this specific classification isolates components dedicated solely to water treatment. Therefore, parts for machinery that filter or purify other liquids (e.g., oil filters for engines) or gases (e.g., air filters for HVAC systems) would not fall under this designation, even if they share similar physical characteristics.

As this is a leaf node in the HTS classification structure, there are no further subcategories for this specific code. Classification decisions under 8421.99.01.40 will rely on identifying the intended function of the part in relation to water purification. If a component serves a dual purpose or is not definitively identifiable as exclusively for water filtration or purification, further analysis and consultation of Chapter 84 Explanatory Notes may be required to determine the correct classification.