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Waste Characterisation (or ‘Do I need a WAC Test?’)

We often come across confusion about what testing is needed for waste disposal, particularly when it comes to the need for WAC (Waste Assessment Criteria) testing and different types of licensed landfill.

So we’re keen to help – the process can be boiled down as follows: First you have a think about what might be in your waste material that could make it hazardous. Then you take representative samples of the material and test for those things. Depending on the concentrations you find, the material will be one of two things – Hazardous or Non-Hazardous.

  • If it’s Non-Hazardous then you can stop there and send it to a standard Non-Hazardous landfill with no further testing required. But if you want to try and get a cheaper disposal rate at a landfill licensed to take Inert waste, then you’ll also need to pass the Inert WAC test.
  • If it's Hazardous, you'll have to do a Hazardous WAC test (which is just a sawn down version of the inert one) to establish if your waste needs ‘pre-treatment’ before the landfill can take it.

So just to say again - Non-Hazardous landfills DO NOT need WAC testing to accept waste, but Inert and Hazardous landfills cannot accept waste without one (it’s a basic condition of their permit).

What actually is the WAC test then? Well it’s a standard set of tests which essentially aims to predict how your waste material will react with other waste that it's buried with and also what long term risks it might pose to the groundwater system (i.e. what gets washed out when rainwater percolates through it over the years).

So, in accordance with our never ending mission to be useful, we have put together a nice little flowchart that describes the Waste characterisation process. It’s something we use internally, but we are very happy to share – just email us at and we’ll email you back a shiny new copy.

A couple of extra side points before you go:

Treatment Centres: As the name suggests these are licensed locations which treat waste material with an aim to subsequently either sending it to cheaper rated landfill (e.g reduce the hazardous level of petrol to non-hazardous) or re-use. Their testing requirements may be driven by their particular permit or treatment process, but they will generally always be keen on an Inert WAC test because it gives them a good idea of where they might get the waste to once they have treated the hazardous content. Importantly, they are not landfills and so are not subject to Landfill Tax!

Reclamation Sites: These are sites with an exemption which essentially sets them outside of the Landfill Tax framework. They will have permitted restrictions on the type of material they can take, but typically the waste needs to be proven as Inert, so a WAC test is needed.

If you need some advice or just want to discuss any of the points raised, then please give us a call.