In accordance with their reputation, I’ve found Australians are a pretty relaxed bunch. The two words I’ve heard most often since getting here are “no worries”. It’s even acceptable to wear thongs to the pub, once you understand thongs are flip-flops, and nobody is too hung up on the finer points of etiquette.

There is one serious social faux pas, however — and that is using more than your fair share of water. A large sign in the lush front garden of a house in Brunswick West, a Melbourne suburb, says: “Tank Water in Use”. Friends explain it’s because of the social stigma attached to watering your garden from the mains. Keen gardeners use recycled bathroom or laundry water. Everyone else sticks to drought-tolerant plants or just installs paving or decking outside the house.

Australians take this extremely seriously; water rage is a recognised phenomenon. Offenders are likely to be reported to the local authorities, and worse has happened. In November 2007, a 62-year-old man in Sydney died after a passer-by attacked him for violating water restrictions. In fact, the dead man had been hosing his lawn during permitted hours.

Australia is the driest inhabited continent, with the lowest rainfall rates. This, combined with high evaporation and heavy consumption, means water is at a premium.

In Melbourne, it’s obvious how critical the shortage is. A huge sign on an overpass in the city centre displays the level in the city’s reservoirs. Last week it was 34.6%, down from 38.6% in the same week last year and from almost 75% in 1997.

Melbourne has always been drought-prone — there were sporadic hosepipe bans in the 1860s — but the current situation is graver than ever. The city is in its tenth consecutive year of drought. Locals can water their gardens only two days a week, and between 6am and 8am, and are forbidden to refill their swimming pools or wash their cars, other than using a bucket of water to clean windows, mirrors and lights.

The restrictions are working, to a degree. In 2007, per capita consumption was down to 1930s levels, but a booming population and the continuing drought mean reservoir levels continue to decline. Local authorities are constantly dreaming up new ways to curb water use.

Friends living here recently received shower timers in the post. “We’re only supposed to shower for four minutes,” explains one, before glancing at his wife and adding wryly, “no matter how long your hair is.” “I save water in other ways,” she protests, with mock indignation.

The timers are part of the T155 campaign, to encourage Melburnians to keep their individual consumption below 155 litres a day. It was launched six weeks ago by John Brumby, the premier of Victoria, who likes a cheesy photo opportunity as much as the next politician and wielded a spanner to show how easy it is to install a water-efficient showerhead.

The drought has more contentious repercussions than cutting shower times, though. Water is provided by private utility companies, and when consumers use less, as they have been told to do, the retailers increase rates to maintain their revenues. Prices are expected to almost double by 2013.

Another cause of controversy is the proposal to build a desalination plant on the Bass Strait coast, southeast of Melbourne, which would provide the city with more drinking water but would also emit enormous quantities of carbon dioxide. Last weekend, in an only-in-Australia type of protest, a clutch of Olympians and Aussie Rules players took part in a celebrity surfing contest to show their opposition to the plant.

As unlikely as we are to see Sonia O’Sullivan or GAA stars take to the waves, Australia’s present is Ireland’s future. Last November, Dublin city council engineers said the capital’s water supply is “on a knife-edge”, with shortages expected by 2011 and permanent rationing by 2016. The council is holding a public consultation on 10 proposed options to solve or at least ameliorate the looming crisis, including piping water to Dublin from lakes on the River Shannon, or a desalination plant.

Newly exercised by water-shortage issues, I consulted the Water Supply Project, Dublin Region, website to add my two cents to the consultation process, but was quickly dissuaded by its bureaucrat-speak. (Random sample from the Frequently Asked Questions page: “Is an integrated abstraction plan required to demonstrate the cumulative effect of existing and proposed abstractions within the catchment and also those abstractions leaving the catchment?”) I gave up entirely when I couldn’t figure out where or how I was supposed to have my say. It’s almost as though the council doesn’t really want my input.

Had there been a big “Have Your Say” button on the website, I would have suggested the council follow the Aussies’ example, recognise that building new reservoirs is not sustainable, and instead hammer home the need for everyone to conserve and reuse water. Drought may seem like an alien concept in a damp country such as Ireland, but in a few decades it could be our grim reality. You never miss the water till the well runs dry.

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