If you do choose this option, be aware that ordering the filter, and getting it fitted and certified takes at least three months, so you need to act as early as possible and pay a daily charge if driving within the zone in the meantime.

Step 1 - Choose and order a filter

It's important to fit an approved filter, as this is the only way to get the certificate to prove that your vehicle meets LEZ emissions standards.

Approved suppliers and their contact details can be found in the following document:

Approved equipment lists can be found in the following documents:

Accredited equipment manufacturers can advise you on approved filters for your particular vehicle. We recommend you contact several filter manufacturers and get a minimum of three quotes.

When requesting a filter quotation it's important that you provide (via email or phone):

  • Vehicle make
  • Vehicle model
  • Body type/style (eg motor home/caravan, light 4x4 utility, van)
  • Drive cycle/vehicle use (eg urban/inner city, suburban, motorway/long distance) and percentage of time spent in each type of driving
  • Gross Vehicle Weight (tonnes or kg)
  • Year of manufacture
  • Engine size/displacement (litres)
  • Engine power (bhp/kW)

Approximate cost of buying and fitting a filter

  • The cost of buying and fitting abatement equipment will vary depending on the age, type and usage patterns of your vehicle
  • Buying a filter will cost between £1,800 and £3,500 for most vans, minibuses and other specialist vehicles and between £3,500 and £7,000 for HGVs, buses and coaches
  • Fitting costs are often included in the purchase price, and are generally between £200 and £500 for vans, minibuses and other specialist vehicles and between £300 and £500 for HGVs, buses and coaches
  • For large vehicles or those which have been specially modified, costs may be higher. It may prove cheaper to upgrade to a newer model which meets the standards, rather than retrofit an older vehicle

Maintenance costs

  • Most filters will need to be serviced once a year, depending on how many miles are travelled
  • Some filters can be self-serviced by the vehicle operator, but most require a full service by a suitably trained mechanic. This will cost around £100-£200 for vans, minibuses and other specialist vehicles, and around £150-£350 for HGVs, buses and coaches

We recommend that you seek a range of quotes before making a purchase.

We are not responsible for suppliers failing to respond or for the quotations received.

The table below includes details of accredited suppliers and the vehicles they have filters for:

  Lorries, buses, coaches and heavy specialist vehicles Larger vans, minibuses and specialist diesel vehicles
+44 1594 887414
 Yes  No
Astra Vehicle Technologies
+44 (0) 151 348 5777
 Yes  Yes
Dinex Exhausts
+44 19 25 84 98 49
 Yes  Yes
Emicon Systems
+44 (0)20 3689 2892
Skype: emiconsystems2
 Yes  Yes
+44 (0)1427 810088
 Yes  Yes
Green Urban
+44 (0) 1786 392 110
 Yes  Yes
HJS Emission Technology
+44 (0) 1344 566 050
 Yes  Yes
Pirelli Eco Technology
01279 432450
 Yes  Yes
+44 (0) 1472 208 008
 Yes  Yes

Step 2 - Get it fitted

The supplier of your filter should be able to recommend an approved fitter, who will fit the filter into your exhaust system (often replacing the exhaust silencer).

Make sure you keep all the documentation for the engine and filter, as you'll need to provide this to the Driver and Vehicle Standards Agency (DVSA), formerly VOSA, to get a certificate for your filter.

DVSA are the government agency that carries out annual tests on all lorries, buses and coaches, and licences MOT garages. It also tests filters and issues all certificates showing that vehicles meet the LEZ standards.

Step 3 - Get it certified

Once your filter has been fitted, it'll need to be tested so you can get your Reduced Pollution Certificate (RPC) or Low Emission Certificate (LEC) to prove your vehicle meets the LEZ emissions standards. You can get a LEC for all types of vehicle, but RPCs are only issued to certain lorries, buses and coaches.

You can either have your filter tested by an Authorised Examiner or at a DVSA test station.

Option 1: Book and take a test with DVSA

Each DVSA test costs £32. To find your nearest centre and book your test, call 0300 123 9000.

DVSA will examine your vehicle to confirm that the filter fitted is approved, and will carry out a smoke test to confirm that it's fitted and functioning correctly (the smoke test doesn't measure the particulate matter emissions of your vehicle). Once the test is successfully completed, DVSA will issue either a LEC or RPC and submit this to us automatically.

It may take up to 10 days for our database to be updated, so in the meantime, you'll need to pay the daily charge if you're driving in the LEZ.

Find out about specialist tests for lorries on the DVSA website

Option 2: Take a test on site with an Authorised Examiner

You may find that the fitter of your filter is a DVSA Authorised Examiner (AE), which means they will be able to test your vehicle for you (and you won't need to book a separate test with DVSA). A fee of £32 will be charged for the test. If not, your filter supplier may be able to recommend a mobile AE who can carry out the test for you at your premises.

Once the test is successfully completed, the AE will submit documentation to DVSA, which will conduct a quality check on the documentation received.

If everything is in order, DVSA will issue either a LEC or RPC to the vehicle owner by post and will notify us that the certificate has been issued.

It may take up to 10 days for our database to be updated, so in the meantime, you'll need to pay the daily charge if you're driving within the LEZ.

Remember to re-test every year

RPCs and LECs are normally valid for 12 months, after which you'll need to get your vehicle re-tested, or pay the daily charge if you're driving within the LEZ.

If you have a lorry, bus or coach, your first RPC or LEC will be valid until your next annual vehicle inspection at DVSA to allow you to schedule the test at the same time.

If you have a larger van or minibus, you will need to get your vehicle re-tested at a DVSA test centre or at any one of the participating non-DVSA LEC testing sites.

Find a list of sites where vehicles can be taken for an LEC test on the GOV.UK website

Please contact the site directly. This test is separate to your normal annual MOT. Please note that most AEs can only test filters the year they are fitted.

When presenting your vehicle at a DVSA test station or to an AE you must produce the previous original LEC issued to the vehicle.

Please check the current fees for a LEC test by DVSA and for certificates issued following an examination by an AE. Any additional fees incurred for tests carried out at an approved AE site should be discussed with the approved AE directly.

It is very important to:

  • Follow the filter manufacturer's maintenance schedule so that the filter doesn't block
  • Heed any warning lights or loss of vehicle performance and contact the filter installer if this occurs. It may mean that there is a build-up of soot in the filter that has not burned off. The trapped soot has a similar chemical composition to coal and needs to burn off at high temperatures. If the filter becomes overly laden with soot it can lead to increased back pressure, which can cause the trapped soot to combust and release heat. This can cause the filter to fail rapidly and means the vehicle would no longer pass the annual test at DVSA