Water filters and air purifiers from China

0% duty on heading 8421

Read from the UK Trade Tariff on 29 September 2026, every line of heading 8421 in the table below carried 0% on goods from China, with no anti-dumping duty. That covers water filters and reverse osmosis units, beverage filtration, engine oil, fuel and air filters, catalytic converters, air purifiers and dust filtration, and parts including reverse osmosis membranes.

Classification still matters for the paperwork. A water purifier is 8421 21, an air purifier or dust filtration unit 8421 39 25, an engine oil filter 8421 23 and an intake air filter 8421 31. Replacement cartridges are usually parts under 8421 99, but loose filter media such as filter paper or felt can fall elsewhere; see filter cloth and technical textiles. Confirm the commodity code from the specification, and remember import VAT at 20% still applies.

Water filters connected to the mains supply

In England and Wales, a filter or reverse osmosis unit plumbed into the water supply is a water fitting under the Water Supply (Water Fittings) Regulations 1999. Regulation 4 requires every water fitting to be of an appropriate quality and standard and suitable for how it is used, which in practice means conforming to an appropriate British Standard or equivalent national specification, or a specification approved by the regulator, and being installed in a workmanlike manner. Scotland and Northern Ireland have their own equivalent rules.

UK installers and merchants usually ask for evidence that the fitting and its materials are suitable for contact with drinking water, so ask the factory which materials touch the water and for test reports on them. Jugs and bottles with filters are not plumbed in but are still articles in contact with food; see food contact materials. Reverse osmosis units also need a backflow arrangement on the drain connection, which your installer will check.

Air purifiers and electrical filtration units

A mains-powered air purifier, water purifier with a pump or UV lamp, or industrial filtration unit with a motor falls under the Electrical Equipment (Safety) Regulations 2016 for 50 to 1,000 V AC and usually the Electromagnetic Compatibility Regulations 2016. Larger industrial units with moving parts, such as dust collectors with fans, are machinery under the Supply of Machinery (Safety) Regulations 2008. Each needs a declaration of conformity, UKCA or CE marking and the importer's name and address; see our CE and UKCA guide.

Performance claims are where filter products get into trouble. A HEPA grade, a clean air delivery rate, or a claim to remove viruses, allergens, lead or microplastics needs a test report on the actual product and filter behind it, and UK advertising rules expect claims to be backed by evidence. Ask for the report, check it names the model you are buying, and print only what it supports.

What to check before shipment

For water filters, check the housing and fittings for leaks under pressure, the thread sizes against UK fittings, the cartridge fit, and the materials list against the test reports. For reverse osmosis units, check the membrane model and the pump and tank if fitted. For air purifiers, check the filter grade printed on the filter against the report, the fan speeds, noise and the plug and fuse.

Replacement cartridges are the repeat revenue in this category, so agree the cartridge price, availability and pack format before the first order, and inspect cartridges as carefully as units. Quality inspection sets out the stages.

Worked duty example

Illustrative example, not a quote: 1,000 own-brand air purifiers under 8421 39 25 90, invoiced at £38,000 free on board, with £2,000 of freight and insurance to the UK. The customs value is £40,000. Duty at 0% is nil. Import VAT at 20% is £8,000, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Related guides and how we help

For related products see water pumps and circulators, activated carbon and filter aids, own-brand small appliances and automotive aftermarket parts.

Cambridge China Bridge checks filtration makers in China, matches test reports to the product and inspects before shipment; see product development, testing and certification and our service for brands.