VENM and ENM are NSW waste classification terms that decide whether fill material can legally be brought onto your property to backfill a former pool excavation, and they matter because using the wrong classification of fill, or fill that hasn’t been properly assessed, can create a genuine environmental and legal problem buried in your backyard. This guide explains what the two terms mean, how they differ, and why the classification of your backfill material is worth understanding even though it’s rarely the first thing homeowners think to ask a pool removal contractor about.
This is general information to help you ask the right questions, not a substitute for site-specific advice from your contractor or the NSW Environment Protection Authority (EPA). Waste classification rules are detailed and can change; always confirm the current position for your specific job.
Why Fill Classification Applies to a Pool Backfill Job
Filling in a former pool excavation isn’t simply a matter of tipping soil into a hole. Any material brought onto a property to backfill an excavation is a “resource” (or, depending on its origin and condition, a “waste”) under the NSW Protection of the Environment Operations Act 1997 and the associated waste classification framework administered by the EPA. Material that’s actually waste, or that could be contaminated, has to be handled, transported and classified correctly before it can be reused as fill. This framework exists to stop contaminated or unsuitable material from being spread onto residential land under the guise of “clean fill”, which has been a genuine problem in parts of NSW when unregulated fill has turned out to contain asbestos, other contaminants or unsuitable waste.
For a straightforward pool fill-in, most of what goes back into the hole is either material excavated from the site itself (the pool rubble and surrounding soil) or imported fill brought in specifically for the job. Both of those categories are where VENM and ENM become relevant.
What Is VENM (Virgin Excavated Natural Material)?
VENM stands for Virgin Excavated Natural Material. Broadly, it refers to natural material, such as clay, gravel, sand, soil or rock, that’s been excavated from land that hasn’t been used for anything other than agriculture or another activity that wouldn’t have introduced contamination, and that doesn’t contain any manufactured or foreign matter, including material like bricks, concrete or tile fragments, as part of its accepted definition. Because it’s inherently “clean” by definition and origin, VENM generally doesn’t need a resource recovery exemption or approval to be reused as fill; it can move between sites with comparatively little regulatory overhead, though the person supplying or receiving it still needs reasonable grounds to believe it genuinely meets the definition.
For a pool backfill job, virgin, uncontaminated natural soil or quarry-sourced material that meets the VENM definition is the simplest category to work with.
What Is ENM (Excavated Natural Material)?
ENM stands for Excavated Natural Material, and it’s a step down in “automatic” clean status from VENM. It covers natural material excavated from land that may have some history of general urban development or other activity, meaning it can’t automatically be assumed to be free of contamination the way VENM can. ENM can still be legally used as fill, but only where it’s been assessed, sampled and classified against the criteria set out in the applicable NSW EPA resource recovery order and exemption for excavated natural material, and typically accompanied by supporting documentation (often referred to informally as a “resource recovery certificate” process) confirming it meets those criteria before it can be received at a site and reused as fill.
In practice, ENM is common where fill is sourced from broader construction and demolition or civil works sites rather than a genuinely undisturbed, never-developed parcel of land. It’s a legitimate, widely used fill category, but it comes with a documentation trail that VENM generally doesn’t require to the same extent.
VENM vs ENM: The Practical Difference for a Pool Backfill
| VENM | ENM | |
|---|---|---|
| Source | Land with no history of contamination-risk activity | Land that may have some development or disturbance history |
| Contamination assumption | Assumed clean by definition and origin | Must be tested and classified before reuse |
| Documentation needed | Minimal, reasonable grounds required | Sampling, classification and supporting records against EPA criteria |
| Common source for pool jobs | Quarry-sourced natural fill, genuinely virgin site soil | Fill sourced from broader civil, demolition or urban development sites |
Both categories can be entirely appropriate for a pool backfill, provided the material is correctly classified and sourced through a supplier who can demonstrate that classification, whether that’s a quarry providing VENM or a supplier providing properly classified and certified ENM.
What This Has to Do With Your Own Pool Rubble
The classification framework isn’t only about imported fill coming onto your property, it also applies, in principle, to material leaving the site. Crushed concrete rubble from your own pool demolition is typically sent to a licensed recycler rather than reused directly as pool backfill in most cases, partly because processed, quality-controlled recycled aggregate performs more predictably under compaction than raw, freshly broken rubble. Where a contractor does propose reusing crushed on-site material as part of the backfill, ask how it’s being assessed and whether it’s free of contaminants (old pool chemicals, timber, coping adhesives) before it goes back into the hole. This sits alongside the separate question of whether any asbestos-containing material is present in the pool surrounds, which is a distinct assessment and removal process handled only by a licensed asbestos removalist.
Why This Matters for Compaction and Certification
Fill classification and compaction quality are related but separate concerns. A load of fill can be correctly classified as VENM or ENM and still perform poorly under compaction if it contains too much clay, organic matter or oversized particles for the intended use. Equally, well-graded, easily compactable material still needs to be legitimately classified before it’s brought onto your property. Both matters should be documented: the compaction side through the testing and certification process covered in our guide on soil testing and compaction certification after pool fill-in, and the classification side through your contractor’s or fill supplier’s records showing where the material came from and how it was classified.
If you’re planning to build over the filled area eventually, a geotechnical report after pool fill-in will assess the placed fill’s engineering properties directly, but it doesn’t replace the separate question of whether the fill was legitimately sourced and classified as VENM or ENM in the first place. Keep records of both.
What to Ask Your Contractor Before Fill Goes In
Before backfill goes in, it’s reasonable to ask: where the material is sourced from and whether it’s supplied as VENM or ENM; if it’s ENM, whether there’s evidence it’s been classified and certified against the applicable EPA criteria; whether any of your own pool rubble or on-site material is proposed for reuse and how it’s been assessed; and whether you’ll receive documentation (dockets, classification records) to keep with your property file. A contractor who sources fill through an established quarry or licensed supplier should be able to answer all of this without hesitation. For a practical look at where that fill physically comes from and what it costs per cubic metre, see our guide on pool backfill dirt cost.
VENM vs ENM Pool Backfill: FAQs
Does every pool backfill job need VENM specifically? No. Both VENM and properly classified ENM are legitimate fill categories for a pool backfill. What matters is that whichever category is used, it’s genuinely sourced and, in the case of ENM, correctly assessed and documented before it’s brought onto your property.
Can I use soil from my own property to backfill the pool? Soil excavated from your own site, where it’s genuinely uncontaminated and hasn’t been affected by the pool’s chemicals, plumbing or surrounds, can often be reused, subject to it being suitable material for compaction. Your contractor should assess this rather than assume all excavated on-site soil is automatically fine to reuse.
Is crushed concrete from my old pool the same as VENM? No. Crushed concrete is manufactured material (processed demolition waste), not virgin natural material, so it sits in a different waste category to VENM or ENM. It’s typically handled through concrete recycling channels rather than reused directly as classified fill, though a contractor may propose reusing some processed material as engineered fill depending on the job.
What happens if unclassified or contaminated fill is used in my pool backfill? This can create both a compliance problem and a genuine engineering and environmental issue buried under your property, potentially affecting future building certification, site value and disclosure obligations at sale. It’s a strong reason to ask about fill sourcing and documentation upfront rather than after the fact.
Want your pool backfilled with properly sourced, documented fill? Get a free quote and we’ll explain exactly where the fill for your job comes from and how it’s classified before any of it goes in the ground.