A little-known law could see residents in one state fined up to a whopping $18,000 for performing a common household chore.
In Victoria, an obscure rule makes it illegal to vacuum your house after 10pm or before 7am on weekdays, or 9am on weekends.
The act is prohibited under the Environment Protection Regulations, which explicitly prohibit the noise of vacuum cleaners outside of these hours. Authorities can issue a 72-hour noise abatement direction to stop the noise.
Failure to comply with a direction can result in a hefty on-the-spot fine of $18,655.20, with ongoing daily breach rates of $4,663.80.
This niche illegal activity was recently rehashed in a local Melbourne Facebook group post, with locals quick to ridicule the rule.
Many were at pains to explain that there are far more frustrating noisy night-time acts committed by their neighbours - from loud music and shouting to barking dogs and screeching car tyres.
'If the guy across the road and two doors over can play his doof doof every day and every night loud enough I can hear it, I am vacuuming and mowing my lawn,' replied one much-liked comment.
Others took light-hearted jibes at the rule.
'I can't be vacuuming after 10pm anyway - that's when I fire up the leaf blower,' laughed one person.
'2am milkshakes for all,' another joker added. 'I do my best blending then.'
Another local woman cheekily replied: 'My husband's snoring sounds like a vacuum. Is it illegal?'
The law, from Section 48A, Environment Protection Act 1970 (Vic); Regulation 6, Environment Protection (Residential Noise) Regulations 2008 (Vic), states that a noise is considered unreasonable if it can be heard in a 'habitable' room in any other residential property, whether the door or window is open or closed.
In New South Wales along with most other states, vacuuming at night isn't strictly illegal, but it can fall under the definition of 'offensive noises' in local jurisdictions, with its use restricted during certain late-night hours.
Vacuuming at night isn't the only unlikely act that can attract fines in The Garden State.
Another bizarre Victorian offence is flying a kite to 'the annoyance of any person' in a public place. According to Section 4, Summary Offences Act 1966 (Vic), this can attract a maximum penalty of a $777.30 fine.
Here's another interesting plainly stated criminal act: it is illegal to correspond or do business with pirates in Victoria, as per Section 70C, Crimes Act 1958 (Vic). The maximum penalty is 10 years' imprisonment.
New South Wales
Commuters in Sydney and other NSW locations waiting on the kerb for a bus on a rainy day needn't worry about being splashed by a passing vehicle - there's a law to protect them.
Drivers can be fined up to $2,200 for not taking enough care to avoid splashing mud on public bus passengers (Regulation 291-3, Road Rules 2014 (NSW)).
South Australia
Barnstorming into a wedding ceremony to shout 'I object' may be commonplace in movies, but interrupting a wedding in South Australia could lead to a huge fine or even imprisonment.
According to Section 7A of the Summary Offences Act 1953 (SA), obstructing or disturbing a wedding - as well as a funeral or religious service - is an offence that carries a maximum fine of $10,000 or two years' imprisonment.
Oh, and if you're ever considering playing 'knock and run' in Adelaide or another South Australian town, think again.
A $250 maximum penalty can apply to someone who willfully pulls or rings the doorbell of a house or knocks at the door, without a reasonable excuse, as per the Summary Offences Act 1953 (SA).
Queensland
Scamming catfishers - take note! In Queensland, it is illegal to post a fake job advertisement, or publish false notices about engagements, births, deaths, or funerals. The act attracts a maximum penalty of a $1,219 fine or six months' imprisonment (Section 21, Summary Offences Act 2005 (Qld)).
And if you're a Queenslander hoping to own a pet, it won't be a rabbit. Under the Biosecurity Act 2014, rabbits are considered destructive to agriculture and the environment, and the fine for having one is up to $71,875.
There is a small loophole; however: those who need rabbits for public entertainment , such as a magic show, or for scientific research - can obtain a permit.
Western Australia
There are a number of quirky laws in Western Australia, but the standout has to do with potatoes.
In WA, it is an offence to possess more than 50kg of potatoes, unless you have purchased them from a grower or retailer authorised by the Potato Corporation.
Police even have the power to stop and search a vehicle suspected of carrying more than 50kg of potatoes.
Under Section 22, Marketing of Potatoes Act 1946 (WA), the maximum penalty is a $2,000 fine for a first offence or a $5,000 fine for subsequent offences, as well as a further penalty up to twice the value of the potatoes.
Another interesting WA law: it's an offence to make a sign that offers a reward for the return of stolen or lost property - if you promise not to ask any questions.
This no-questions-asked addition on a lost property sign attracts a maximum penalty of a $2,000 fine (Section 138, Criminal Code Act 1913 (WA)).
Northern Territory
In the far north, it is an offence for a pedestrian to walk on the road when a pathway or nature strip is available, attracting a maximum fine of $3,080 or six months' imprisonment.
Tasmania
Like to drop a swear? Don't do it in Tassie.
According to the Police Offences Act 1935, article 12, in public it is illegal to curse or swear; sing any profane or obscene song; use any profane, indecent, obscene, offensive or blasphemous language; or use any threatening, abusive or insulting words or behaviour.
Australian Capital Territory
Even Australia's capital territory has an unusual law for homeowners: no front fences allowed.
The decree was originally made by British planner-architect Sir John Sulman, chairman of the Federal Capital Advisory Committee (FCAC) in 1921 in the interests of fostering open plan neighbourhoods.
While front fences aren't permitted, soft enclosures like hedges are fine.
So next time you reach for your vacuum cleaner or consider buying a mammoth amount of potatoes, remember: in Australia, even the simplest acts can land you in hot water.