How Long Does Cannabis Stay in My System?

If you are asking, “How long does cannabis stay in my system?”, you are not alone. It is one of the most common questions asked by drivers in Victoria. Unfortunately, there is no simple answer. 

How long cannabis stays in your system depends on a range of factors, including how often you use it, how much you consume, your metabolism, and the type of test being used. Importantly, the amount of time cannabis remains detectable is often much longer than the period during which you actually feel impaired.

For drivers in Victoria, this distinction is critical. The law does not require police to prove that you were affected by cannabis. Instead, for many offences, the prosecution only needs to prove that tetrahydrocannabinol (THC), the active component of cannabis, was present in your system while you were driving.

How do police test for cannabis?

Victoria Police use roadside oral fluid (saliva) testing to detect the presence of certain illicit drugs, including THC.

If the roadside test returns a positive result, a second oral fluid sample is taken for laboratory analysis. If the laboratory confirms the presence of THC, you may be charged with a drug driving offence.

Unlike drink driving, police are not measuring the amount of cannabis in your system. The test is designed to detect its presence.

How long can cannabis be detected?

There is no fixed timeframe.

Detection times vary depending on several factors, including:

• how much cannabis was consumed;

• whether it was smoked, vaped or ingested;

• how frequently it is used;

• your body composition and metabolism; and

• the sensitivity of the testing method.

For occasional users, THC may only be detectable in saliva for a relatively short period after use. However, for regular or heavy users, it may remain detectable for considerably longer.

Because of these variables, it is impossible to say exactly when it will no longer be detected.

Does feeling sober mean I can drive?

No.

Many people assume that once the effects of cannabis have worn off, they are safe to drive.

Unfortunately, that is not how Victorian drug driving laws operate.

You may no longer feel impaired but still return a positive roadside drug test.

The safest approach is to avoid driving after consuming cannabis until you are confident it is no longer detectable.

Does medicinal cannabis make a difference?

Medicinal cannabis does not automatically exempt you from Victoria’s drug driving laws.

If your medicinal cannabis contains THC, you may still commit a drug driving offence if THC is detected while you are driving.

This surprises many patients who are lawfully prescribed medicinal cannabis by their doctor.

There are limited legal exceptions in some Australian jurisdictions. However, in Victoria, drivers should obtain legal advice if they are unsure how the law applies to their prescription.

Does CBD show up on a roadside drug test?

Pure cannabidiol (CBD) is different from THC.

CBD products that contain no THC are not intended to trigger a roadside drug test.

However, some medicinal cannabis products contain both CBD and THC.

If your medication contains THC, you may still test positive even if you are using it exactly as prescribed.

You should always understand the ingredients contained in your medication before driving.

Can drinking water or brushing my teeth help?

No.

There is no reliable method of quickly removing THC from your saliva or avoiding detection.

Common myths, including:

• drinking large amounts of water;

• using mouthwash;

• chewing gum;

• brushing your teeth; or

• eating certain foods,

have not been shown to reliably prevent a positive roadside drug test.

Attempting to manipulate the testing process is unlikely to be successful.

Can I contest a drug driving charge?

Yes.

Like any criminal offence, a drug driving charge can be contested if there is a proper legal basis to do so.

Possible issues may include:

• whether the testing procedures were properly followed;

• whether the laboratory analysis complied with legal requirements;

• whether the prosecution can prove every element of the offence; or

• whether there are other factual or legal issues affecting the case.

Every matter should be assessed individually before deciding whether to plead guilty or contest the charge.

What are the penalties for drug driving?

The penalties for drug driving depend on:

• the type of offence;

• whether it is a first or subsequent offence;

• your traffic history; and

• the applicable Victorian legislation.

Depending on the circumstances, penalties may include:

• a criminal conviction;

• fines;

• licence cancellation or disqualification;

• mandatory education programs; and

• alcohol or drug interlock requirements in some cases.

Obtaining legal advice early can help you understand the likely consequences in your particular case.

Speak to an experienced drug driving lawyer

If you have been charged with drug driving after testing positive to cannabis, it is important to obtain advice before deciding how to proceed. Every case is different, and the outcome will depend on the evidence, the testing procedures and your individual circumstances.

At Wilkinson Lawyers, we regularly advise and represent clients charged with drug driving offences throughout Victoria. We can explain the allegations, review the evidence and help you achieve the best possible outcome in your case.

Contact Jess Wilkinson on 0468 364 121 or jess@wilkinsonlawyers.com.au to discuss your matter and obtain advice about the best way forward.