Pre-Purchase Vehicle Meth Testing: The Complete Buyer's Guide for Used Cars and Caravans in Australia

Just as pre-purchase meth testing for properties became standard practice for prudent buyers over the past decade, a growing number of Australians are realising that the same logic applies to used vehicles. The difference is that the used vehicle market has almost none of the disclosure protections that now exist — however imperfectly — in the property market. No PPSR check, no CarHistory report, no RevCheck — none of these will tell you whether the car you are about to buy has methamphetamine contamination. This guide walks through everything a buyer needs to know.

Why Vehicle Meth Contamination Is a Growing Problem

Australia consumed 12,815 kg of methamphetamine in 2023–24 — a 21% increase on the prior year (ACIC National Wastewater Drug Monitoring Program, Report 24). This figure is not background noise. It is context for understanding why vehicle contamination is not a niche or fringe problem affecting a handful of edge-case buyers. A significant proportion of methamphetamine use in Australia happens in vehicles, because vehicles offer privacy, mobility, and an enclosed space that many users prefer over their home or elsewhere. The contamination left behind is invisible and odourless at typical concentrations, and — critically — it persists indefinitely. Methamphetamine does not break down naturally on surfaces. It does not diminish over time. It does not evaporate. A vehicle contaminated three years ago remains contaminated today, at the same level, unless it has been professionally remediated and verified.

What makes vehicles particularly high-risk compared to residential properties is a combination of physical and market factors working together:

• Small cabin volume concentrates contamination: A typical car interior is 2.5 to 3.5 cubic metres. The same quantity of methamphetamine vapour released inside a car cabin deposits on surfaces at concentrations 10 to 100 times higher per unit area than in a house. This is why vehicles regularly test at levels of 10, 20, or 50+ micrograms per 100 cm² — far above the Australian guideline of 0.5 µg/100cm².
• Multiple materials absorb and retain contamination: Headliner fabric, seat upholstery, carpet, door panel padding, seatbelt webbing — all absorb methamphetamine into their fibres. Unlike a painted wall that can be wiped down, porous textile materials trap residues at depth where surface cleaning cannot reach.
• The HVAC system actively redistributes contamination: When methamphetamine is smoked in a vehicle, the heating and air-conditioning system draws contaminated air through its ductwork, depositing residue on the evaporator coil, heater core, and all internal surfaces. Every subsequent time the HVAC is operated, it re-disperses that residue into the cabin. You can detail every visible surface and still have the air conditioning pumping contaminated air onto the occupants.
• No disclosure laws exist for vehicle sales: Unlike the property market — where New South Wales requires disclosure of drug manufacturing history for the past two years, and Victoria has similar requirements — there is no jurisdiction in Australia that requires a vehicle seller to disclose drug contamination. A car can test at 300 times the residential guideline and be sold the next day with a clean PPSR certificate and a freshly detailed interior.
• Vehicle history checks contain no contamination data: PPSR, CarHistory, RevCheck, AutoCheck — none record anything related to drug use, drug seizure, or environmental contamination.

In March 2025, Flinders University researchers published the first peer-reviewed study specifically examining vehicle methamphetamine contamination distribution. Testing two vehicles with known links to drug activity, they found that 85% of surface wipe samples, 93% of bulk material samples, and 100% of air samples were positive for methamphetamine. The lead researcher called for dedicated regulations for vehicle contamination — which, as of the date of this article, do not exist anywhere in Australia.

The combination of rising national use, a used vehicle market with no disclosure obligations, and standard vehicle history checks that are completely blind to contamination creates a genuine consumer protection gap. The only way to close that gap, before you commit to a purchase, is to test.

Who Should Test Before Buying

Almost any used vehicle purchase warrants at least consideration of contamination testing, but the risk level varies significantly by context. This guide sets it out as a practical risk framework rather than a blanket recommendation.

A note on police and government auction vehicles: This category warrants special mention because it is counterintuitive. You might assume that a police-seized vehicle would be tested and cleared before re-sale. In most Australian states, this is not the case. Government auction vehicles — including those seized from drug operations — are typically sold "as is, with all faults." There is no mandatory testing, no mandatory remediation, and no mandatory disclosure of the reason for seizure. Test Australia's suitably qualified occupational hygienists have tested police auction vehicles that were contaminated at levels hundreds of times above the residential guideline. Buyers at these auctions routinely assume that a seized vehicle must have been assessed and made safe. That assumption is wrong.

What Vehicle History Checks Don't Tell You

Before committing to a used vehicle purchase, most informed buyers run some combination of the following checks. Here is precisely what each one does and does not tell you about contamination.

PPSR — Personal Property Securities Register

The PPSR is the national database of security interests registered against personal property, including motor vehicles. A PPSR check ($2 via ppsr.gov.au) will tell you whether the vehicle has outstanding finance (a security interest registered against it), whether it has been reported stolen, and whether it is recorded as a statutory write-off. It will not tell you anything about the vehicle's use history, any prior drug-related seizure, or any form of environmental contamination. The PPSR is a financial and legal status database. Contamination is not a financial or legal status that anyone is required to register.

CarHistory, RevCheck, AutoCheck, CarFacts

These are commercial services that aggregate multiple data sources — primarily PPSR data, registration history, odometer readings, and manufacturer recall notices — into a single report. Some services also include information about insurance write-offs across multiple states. None of these services record or have access to drug contamination data. They cannot tell you. No such data exists in any database they can query. A clean CarHistory report for a contaminated vehicle is not anomalous or a failure of the service — it is simply the reality that contamination data is never recorded anywhere.

ANCAP Safety Ratings and Service History

ANCAP ratings are vehicle model assessments, not individual vehicle assessments. Service history records mechanical maintenance and wear — not chemical contamination of the cabin environment. A full service history from the original dealer says nothing about how the cabin was used between services.

The contrast with property disclosure obligations is instructive. In New South Wales, a vendor selling a property must disclose whether it was used for drug manufacturing in the past two years. Victoria has similar requirements. Queensland has guidelines for real estate agents requiring contamination disclosure when known. No equivalent obligation exists for vehicle sellers in any Australian jurisdiction. A seller who knows their car is contaminated is not legally required to tell you, and no check you can run will reveal what they know and are not disclosing.

This is not a hypothetical concern. A vehicle can test at 300 times the Australian meth guideline — contaminated to a degree that would cause a property to be condemned as uninhabitable — and be sold through Carsales, Gumtree, or Facebook Marketplace the following morning. The buyer has no legal protection against this scenario unless they have independently tested the vehicle before purchase, or unless they can later prove the seller had actual knowledge and deliberately concealed it.

Red Flags to Look For

It is important to be precise about what red flag analysis can and cannot achieve. No visual or olfactory inspection can reliably detect meth contamination — methamphetamine residue is invisible at concentrations far above the investigation level, and the chemical itself is odourless as a surface residue. However, certain observable features increase the probability that contamination is present, and their presence should make you more emphatic about getting a test done.

• Excessive or unusual air fresheners: Particularly strong pine, citrus, or vanilla masking agents — especially multiple air fresheners, or fresheners placed directly in vents where they would circulate scent through the HVAC system. A single air freshener is normal. Four air fresheners and a spray can of fabric deodoriser in a vehicle with otherwise light use is not.
• Heavy recent interior detailing inconsistent with vehicle age: A 2015 model presenting with showroom-fresh carpet and steam-cleaned seats but worn exterior trim, worn tyres, and faded paint suggests the interior was recently heavily cleaned — potentially to address contamination rather than for aesthetic reasons.
• Incomplete or replaced interior components: New carpet in an older vehicle, a recently replaced headliner (particularly if the repair edges are visible), seats that don't match the rest of the interior, or a clean boot liner in an otherwise worn vehicle. These suggest selective replacement of the most contaminated components rather than general restoration.
• Brown or yellowish staining on the headliner fabric: Meth vapour condenses on the headliner as it rises to the ceiling. In vehicles with heavy use, this can leave visible discolouration — a slight yellow or brownish tint that cannot be cleaned away because it has penetrated the fabric. This is one of the few visible indicators of contamination.
• Unusual chemical smell, particularly from the vents: While methamphetamine itself is odourless as a surface residue, the solvents and chemicals associated with drug use — including acetone, ammonia, and various cleaning agents — can leave a faint chemical odour that is most apparent when the HVAC system forces air through contaminated ductwork. If you smell something unfamiliar when turning on the air conditioning, note it.
• HVAC system recently serviced or components replaced: A recently replaced cabin air filter, or evidence that the ducting has been accessed, in a vehicle where this is not consistent with normal service intervals, may indicate an attempt to address duct contamination.
• Aftermarket modifications to the ventilation system: Blanked-off vents, modified air intakes, or unusual additions to the cabin air system may indicate the HVAC system was modified during use or as part of an incomplete remediation attempt.

Testing Options Available

There are three categories of vehicle meth testing available to buyers in Australia. They differ substantially in what they can tell you, what they cost, and what you can do with the results.

Option 1: Professional Testing with NATA-Accredited Laboratory Analysis (Recommended)

This is the forensic standard. A trained assessor — ideally a Chartered Chemist (MRACI CChem), registered occupational hygienist, or forensic scientist — attends the vehicle and collects wipe samples using NIOSH 9111 methodology from six to eight critical locations. The sampling kit, sample collection method, and chain of custody documentation all follow validated protocols. Samples are submitted to an independent NATA-accredited laboratory for gas chromatography–mass spectrometry (GC-MS) analysis. Results are reported in micrograms per 100 cm² with appropriate measurement uncertainty estimates. A written report prepared by the assessor provides interpretation, comparison against the 0.5 µg/100cm² Australian guideline, and recommendations.

• Cost: From approximately $595 for a standard passenger vehicle, with more for caravans and motorhomes
• Turnaround: 3–7 business days for full report
• What the result tells you: Whether contamination is present, at what level, and whether that level exceeds the guideline
• Can be used for: Insurance claims, legal proceedings, dealer disputes, Consumer Affairs complaints, and significant purchase decisions
• Suitable for: Any purchase decision above approximately $15,000, all caravans and motorhomes, and any vehicle where legal remedies may be needed

Option 2: DIY Presumptive Test Kits

Lateral flow immunoassay test strips — essentially the same technology as a COVID-19 rapid antigen test — are applied to vehicle surfaces using a moistened applicator. A colour change indicates the presence or absence of methamphetamine. These kits are available from some pharmacies and online retailers, typically costing $30–50 each. You would generally use three to five per vehicle for a meaningful preliminary screen — one on the steering wheel, one on the headliner, one on the dashboard, one on a seat surface, and one on an air vent.

• Cost: $90–$250 for a meaningful vehicle screen using 3–5 kits
• What the result tells you: Presence or absence — not concentration. A positive does not tell you whether contamination is at 0.6 µg/100cm² or 60 µg/100cm².
• Limitations: High false positive rates with some formulations. No quantification. Not accepted for any legal, insurance, or formal purpose. Not analysed by a NATA-accredited laboratory
• Can be used for: A preliminary first-pass screen only
• Suitable for: Initial screening. A negative result across multiple sites provides some reassurance but is not definitive. A positive must be confirmed by laboratory analysis before acting on it

Option 3: Composite Laboratory Testing

Multiple wipe samples are physically combined into a single composite sample before laboratory submission. This reduces the cost compared to submitting each sample individually, but at the cost of spatial resolution — a positive result tells you contamination is present somewhere in the vehicle but cannot identify which location. Useful for a lower-cost screening approach where the primary question is "is contamination present at all." A positive composite result should be followed up with individual-location sampling to identify the source and extent before decisions are made about remediation.

• Cost: Lower than individual sample testing, and varies by provider
• Suitable for: Initial screening where cost is a primary constraint and quantitative location data is not yet needed

Test Australia's recommendation: For any significant purchase decision — particularly a caravan, motorhome, or a vehicle over $20,000 — professional NATA-accredited testing is the appropriate level of due diligence. The cost is a tiny fraction of the vehicle's value and provides protection that no other pre-purchase check can offer. DIY kits have a role as a preliminary screen for lower-value vehicles or when you want a quick indication before committing to professional testing.

How Testing Works in Practice

The practical logistics of arranging a pre-purchase vehicle test vary depending on where and how you are buying.

For Private Sales

Request access to the vehicle for 30 to 60 minutes as a condition of your final inspection. A professional assessor can complete wipe sample collection in this time. Most private sellers will not object to a request framed straightforwardly: "I want to get a contamination test done as part of my inspection — is that okay?" Framing it as routine due diligence — which it is — typically produces no resistance from sellers who have nothing to hide.

If a seller refuses to allow a contamination test, treat this as a significant red flag. There is no legitimate reason to refuse a non-destructive surface wipe test. The process takes under an hour, leaves no trace on the vehicle, and does not affect the vehicle's mechanical or cosmetic condition in any way. Refusal is information.

For interstate private purchases where attending in person is impractical, a local testing provider in the seller's city can be arranged to attend the vehicle. This is a well-established service model and does not require your physical presence.

For Auction Purchases

Most major Australian auction houses — Pickles, Manheim, and Grays — allow independent inspections during designated viewing days before the auction. A professional assessor can collect wipe samples from any vehicle during this period. The key timing consideration: if you bid on and win a vehicle before your laboratory results are received, you are committed to the purchase regardless of those results. Auction purchases are typically binding on the fall of the hammer.

The safest auction approach is to attend viewing day, collect samples, wait for results, and only bid if results come back below the guideline. If logistics prevent waiting for results, bidding at a conservative price that accounts for the possibility of contamination and remediation costs is a prudent fallback.

For Dealer Purchases

Dealers are subject to the Australian Consumer Law's "acceptable quality" guarantee. A reputable dealer should have no objection to pre-purchase testing. If a dealer refuses to allow a contamination test during the inspection period, consider purchasing elsewhere — the refusal itself warrants concern. For dealer purchases, you also have the advantage of stronger post-purchase remedies than in a private sale (see the section on what to do if contamination is found).

Understanding the Results

Results from NATA-accredited laboratory analysis are reported in micrograms of methamphetamine per 100 square centimetres (µg/100cm²). Here is how to interpret what those numbers mean.

The Australian Guideline: 0.5 µg/100cm²

This threshold was developed for residential properties by the Australian/New Zealand Standard AS/NZS 8501:2008 (and its predecessor guidance documents) and is the benchmark used nationally for contamination assessment. Below this level, no remediation is typically required and the space — whether a house or vehicle — is considered suitable for occupancy. Above this level, remediation is recommended before the space is used regularly.

One important caveat specific to vehicles: the 0.5 µg/100cm² threshold was developed for properties, not vehicles. In a vehicle's confined space — particularly with the HVAC system recirculating cabin air — inhalation exposure from contaminated surfaces can be proportionally greater than in a property at the same surface concentration level. A level that might be borderline acceptable in a large house may present a materially greater inhalation risk in a small car cabin. Experienced assessors account for this context in their recommendations.

Interpreting Different Concentration Levels

These ranges are indicative, not regulatory categories. The most important comparison is always against the 0.5 µg/100cm² guideline, and the most important practical question is what remediation would cost relative to the vehicle's value. Your assessor's written report should address both of these questions explicitly.

Note also that a result "below guideline" does not mean "contamination-free." It means that measured contamination is below the threshold at which remediation is recommended. Depending on how sensitive the laboratory method is, very low levels of methamphetamine may be detected but reported as below the action threshold. This is an important distinction when interpreting reports that show a detected level versus a below-detection-limit result.

What Happens If Testing Finds Contamination

A positive result does not end the conversation — it opens a set of options. Which option makes sense depends on the contamination level, the vehicle's value, and when in the purchase process the result is received.

Option 1: Walk Away

If contamination is found at levels that make remediation economically unviable — generally above 5 to 10 µg/100cm² in a vehicle where remediation would require full interior replacement — the clearest course is to not proceed with the purchase. In a private sale, you decline. At auction, if you received the results before bidding (the recommended approach), you simply do not bid. This is the cleanest outcome: you spent a few hundred dollars on testing and saved yourself from a potentially very costly mistake.

Option 2: Renegotiate the Price

If contamination is at moderate levels, it may be possible to negotiate a price reduction that reflects the cost of remediation. Before going back to the seller, get written remediation quotes from one or two providers. Knowing that remediation will cost, for example, $3,500 means you can make a concrete, evidence-based proposal to reduce the purchase price by that amount, with the test report and remediation quotes as supporting documentation. Speculative negotiation without specifics is less effective.

Option 3: Require the Seller to Remediate First

For dealer sales, you can request that professional remediation — to below guideline, with verification testing — be completed before you take possession. Get this commitment in writing, specifying the standard to be achieved (below 0.5 µg/100cm² on all sampled surfaces), the verification testing requirement, and the timeline. Verbal assurances are not enforceable. A dealer who agrees to remediate but is not prepared to put it in writing is telling you something important about how seriously they take the commitment.

Option 4: Proceed with Eyes Open

For very low contamination levels — for example, results detected but materially below the guideline — an informed buyer might proceed with the purchase, factor in the cost of professional-grade interior cleaning (not the same as remediation, but appropriate for low-level contamination), and assess the health implications relative to intended use. A vehicle driven daily for a school run warrants more caution at any given contamination level than a weekend project car used occasionally by adults.

If You Have Already Purchased and Discovered Contamination

This is a harder position to be in, but options exist depending on how and where you bought.

For dealer purchases: Contact the dealer in writing — by email, so the communication is documented — citing the Australian Consumer Law's "acceptable quality" guarantee. ACL section 54 requires that goods be safe and fit for their common purpose. A contaminated vehicle is arguably neither safe nor fit for purpose as a vehicle. Request remediation to below the Australian guideline with independent verification testing, or a refund. If the dealer refuses, lodge a complaint with your state or territory consumer protection agency: NSW Fair Trading, Consumer Affairs Victoria, Queensland Office of Fair Trading, WA Consumer Protection, or SA Consumer and Business Services. You can also lodge an online complaint through the ACCC website. For significant amounts, consider engaging a consumer law solicitor — many offer a free initial consultation.

For private purchases: Your options are significantly more limited, and this is the core reason why pre-purchase testing matters more in private sales than in dealer sales. If the seller had actual knowledge of the contamination and did not disclose it, there may be grounds under ACL section 18 (misleading or deceptive conduct by omission) — but establishing the seller's actual knowledge is difficult without evidence. If the seller actively misrepresented the vehicle's history in writing, that is a stronger foundation for a claim. Seek legal advice from a consumer law solicitor before taking action. Do not spend money on remediation without first understanding whether you have a viable claim against the seller to recover those costs.

Caravans and Motorhomes — Special Considerations

Caravans and motorhomes require a different approach to testing compared to passenger vehicles, because they function primarily as living spaces rather than transport vehicles. The contamination risk profile, the sampling methodology, and the economic consequences of a positive result all differ in important ways.

Why Caravans Present Elevated Risk

Caravans and motorhomes are particularly vulnerable to methamphetamine contamination for several interconnected reasons. They are mobile, private, self-contained living spaces — exactly the kind of environment that appeals to drug users who are seeking privacy away from fixed addresses. They are routinely used in remote locations where there is minimal risk of observation. They are bought and sold privately in large numbers, often with minimal recorded ownership history. Hire fleets — where the caravan is regularly used by unknown strangers — represent a particularly high-risk source of second-hand stock.

A standard 6-metre caravan has an interior habitable volume of approximately 15 to 25 cubic metres — much smaller than a house but much larger than a car cabin. This places it in an intermediate contamination concentration range: if methamphetamine is smoked inside, concentrations will be higher than in a house but lower than in a car, per unit area. However, because the caravan is used as a sleeping and living space for extended periods, exposure duration is far greater than in a vehicle — a user sleeping eight hours in a contaminated caravan has more total exposure than the same person driving a contaminated car for two hours a day.

Testing Protocol for Caravans

A caravan or motorhome is assessed using a protocol that more closely resembles a residential property inspection than a passenger vehicle inspection. The habitable area is sampled systematically, typically including:

• Sleeping area — mattress surface and adjacent wall or ceiling panel
• Kitchen bench and splashback surfaces
• Dining or living area — table surface and seating
• Bathroom — vanity surface and any hard wall panels
• Air vent surfaces from the caravan's ventilation or air-conditioning unit
• Door and window reveals — surfaces that accumulate condensed vapour

The number of samples and the specific locations depend on the caravan's layout and size. Larger motorhomes with multiple discrete living zones require proportionally more samples to adequately characterise contamination distribution.

Soft Furnishings and Economic Impact

Caravans contain extensive soft furnishings — fitted mattresses, curtains, upholstered banquette seating, carpet, and cushions. All of these materials absorb and retain methamphetamine at depth, making surface cleaning insufficient for meaningful decontamination. For a contaminated caravan, remediation typically requires the full strip-out of all fabric and foam components: mattresses, seat cushions and their foam bases, curtains, and carpet. In an older caravan or one with custom-fitted furniture, this remediation can cost more than the caravan's market value — making it effectively an economic write-off even at moderate contamination levels.

For this reason, pre-purchase testing is arguably even more important for caravans than for passenger vehicles. The potential downside is large, and there is essentially no consumer protection mechanism that would allow you to recover your money after a contaminated caravan has been purchased privately.

Hire Caravan Risk

Caravans returning from hire fleet represent among the highest-risk used vehicles available in the Australian market. The identity and behaviour of all previous hirers is unknown. The caravan has been used as a sleeping space by potentially dozens of unknown individuals. The hire company's post-rental inspection and cleaning protocol — whatever it is — is almost certainly not designed to detect or address chemical contamination. If you are purchasing an ex-hire caravan, professional testing is not optional due diligence. It is a basic requirement of informed purchasing.

Industry Context and Choosing a Testing Provider

The vehicle meth testing industry in Australia is, like the property testing industry, almost entirely unregulated. There are no licensing requirements, no mandatory qualifications, and no enforceable standards for who can call themselves a vehicle contamination tester. This creates a consumer protection problem that you need to navigate carefully, particularly given that a test result may form the basis of a significant financial decision.

When selecting a testing provider for a pre-purchase vehicle assessment, the criteria are the same as for property testing:

• NATA-accredited laboratory analysis: The laboratory performing the final analysis of your samples must hold NATA accreditation for the specific test method being used (typically GC-MS analysis for methamphetamine). This is non-negotiable. A result from a non-NATA-accredited laboratory cannot be relied upon for any formal purpose and may not even be technically valid.
• Qualified assessors: Look for assessors holding recognised professional credentials: Chartered Chemist (MRACI CChem) from the Royal Australian Chemical Institute, registered occupational hygienist (AIOH), or demonstrable forensic science qualifications. Academic credentials and membership of professional bodies that impose continuing professional development requirements are important indicators of competence and ongoing currency.
• Independence — does not offer remediation services: This is the most important conflict-of-interest check in the industry. A testing provider who also offers remediation services has a direct financial incentive to find contamination. They profit from a positive result. This conflict does not mean every dual-service provider will falsify results, but it does mean the incentive structure is misaligned and the independence of the assessment is compromised. The same entity should not provide both the forensic assessment and the remediation — just as the same doctor should not diagnose a condition and also sell you the drug to treat it. At Test Australia, we do not offer remediation services. Our only financial interest is in providing an accurate, independent assessment.
• Chain-of-custody documentation: Professional testing requires documented chain of custody from sample collection through laboratory submission and analysis. This is what makes results legally defensible. Ask whether the provider can supply chain-of-custody documentation with their report — if they cannot, the results cannot be relied upon in any legal or insurance context.
• Written report with interpretation: A number without context is not useful. A professional report should include the results for each sampled location, the measurement uncertainty, comparison against the Australian guideline, an interpretation of what the results mean for that specific vehicle, and a recommendation about whether remediation is required. A one-page table of numbers is not a professional contamination assessment report.

What About Interstate Testing?

If you are purchasing a vehicle in another state, local testing providers in most capital cities and many regional centres can be engaged to attend the vehicle. When engaging a provider remotely, apply the same criteria: NATA-accredited laboratory, qualified assessor, documented chain of custody, written report. Ask for a sample report before engaging them, so you know what you will receive. If the provider cannot or will not supply a sample report, that tells you something about the quality of their output.

Turnaround Times and Purchase Timing

Allow for realistic turnaround times when planning your purchase. Sample collection can typically be arranged within one to three business days. Laboratory turnaround for GC-MS analysis at a NATA-accredited lab is typically three to five business days, sometimes faster depending on the laboratory's workload. Total time from engaging a provider to receiving a written report is commonly five to ten business days.

For a private sale, this means you need to negotiate a few days' hold on the vehicle pending the test result, or conduct testing early enough in your evaluation process that you have results before finalising a price. For an auction purchase, the critical timing is getting onto the viewing day early enough to collect samples and receive results before the auction date. Build this timeline into your purchase planning from the start — not as an afterthought when you have already committed yourself emotionally or financially to a specific vehicle.

The Case for Testing: A Cost-Benefit Summary

The financial case for pre-purchase vehicle testing is not complicated. Consider a $35,000 used caravan purchased privately. The PPSR check cost $2. The CarHistory report cost $30. Together, those checks told you that the caravan has no outstanding finance and no recorded write-off. They told you nothing about what happened inside that caravan over the previous five years of private and hire use.

A professional contamination test costs approximately $695 to $895 for a caravan of that size. That is approximately 2% of the purchase price. It is the only check that measures the residue in a caravan you will sleep in, cook in, and let your children spend nights in.

If the test comes back negative — below guideline — you have spent less than $900 to confirm that the single largest risk factor not covered by any other check is not a problem. That is money well spent. If the test comes back positive at high levels, you have spent $900 to avoid buying a caravan that might cost $15,000 to remediate (if remediation is even feasible) or that you might otherwise have lived in while being exposed to methamphetamine contamination for months or years before understanding why family members were unwell.

The expected value of the test is positive across a wide range of contamination probabilities. Even if the probability of any given caravan being contaminated above the guideline is only 10%, the expected cost savings from testing before committing to purchase are substantially positive. This is before accounting for the non-financial considerations — health risk to occupants, particularly children, and the certainty that comes from having a documented, evidence-based answer rather than hoping for the best.