HSN codes for filtration and water treatment products
Buyers, accounts teams and importers ask us for HSN codes more than almost anything else. This table lists the HSN headings that are normally used for the products we make, supply and build. It is a starting point for your purchase order or invoice, not a tax ruling.
HSN headings by product
| Product | HSN heading usually used | Notes |
|---|---|---|
| RO, UF and NF plants, softeners, DM, sand and carbon filters | 8421 21 | Machinery for filtering or purifying water |
| ETP, STP and ZLD systems | 8421 21 | Large projects are often billed as a works contract; check with your CA |
| Spun, wound and pleated filter cartridges | 8421 99 or 8421 21 | 8421 99 as parts of filtering equipment is the most common choice |
| Cartridge and bag filter housings | 8421 21 or 8421 99 | Complete housings with elements are usually 8421 21 |
| Liquid filter bags | 5911 or 8421 99 | 5911 covers technical textile articles such as filter felt and mesh |
| RO membranes and membrane pressure vessels | 8421 99 | Parts of water purifying machinery |
| FRP pressure, filter and softener vessels | 8421 99 | Plastic tanks sold on their own can fall under 3925 |
| High-pressure, centrifugal and dosing pumps | 8413 | 8413 70 for centrifugal pumps, 8413 50 for reciprocating dosing pumps |
| Butterfly, ball, diaphragm and control valves; multiport valves | 8481 80 | Taps, cocks and valves |
| Non-return (check) valves | 8481 30 | |
| Rotameters and electromagnetic flow meters | 9026 10 | Instruments for measuring the flow of liquids |
| Pressure gauges and pressure transmitters | 9026 20 | |
| TDS, conductivity, pH and ORP meters | 9027 | Instruments for physical or chemical analysis |
| Ion exchange resin | 3914 | |
| Activated carbon (granular) | 3802 | |
| Antiscalants and membrane cleaning chemicals | 3824 | Depends on the formulation |
Why the same product can carry two codes
A filter cartridge is a part of a filtering machine, so many suppliers bill it under 8421 99. Others bill it under 8421 21 because it filters water on its own. The same applies to housings and vessels. What matters is that you classify the same item the same way every time, and that the code matches how the item is described on the invoice.
Before you invoice
- Use the full 8-digit code from the current Customs Tariff, not just the heading.
- Check the GST rate for that 8-digit code on the CBIC site or with your CA. Rates change.
- For exports, use the same code on the shipping bill and the invoice.
We print the HSN code we use on every Filtsap quotation and invoice. If your accounts team needs a different code to match an existing purchase order, tell us when you request a quote.
FAQs
What is the HSN code for a PP filter cartridge?
Most suppliers use 8421 99 (parts of filtering or purifying machinery). Some use 8421 21. Confirm the 8-digit code and GST rate with your CA.
What is the HSN code for an RO plant?
Industrial RO plants are usually classified under 8421 21, machinery for filtering or purifying water.
What is the HSN code for a filter bag?
Felt and mesh liquid filter bags are often classified under 5911 (technical textile articles). Some suppliers use 8421 99 when the bag is sold as a filter element.
What is the HSN code for a rotameter?
Rotameters and other liquid flow meters fall under 9026 10.