Now many Viennese are up in arms over a movement by restaurateurs to start charging for tap.
It amounts to cultural sacrilege in a city where delicious tap water — fed by Alpine springs — is seen as a birthright, and part of the whole experience of lounging in centuries-old cafes or savoring young wine at one of the Austrian capital's many leafy outdoor eateries.
For now, payment is voluntary, with 11 restaurants participating in a charity campaign meant to collect funds for clean water-starved Sierra Leone. But the establishments pocket half the water fee and prominent restaurateurs are starting to lobby for an obligatory tap water charge, unrelated to aid for Africa, just as the charity program has begun.
Many Viennese suspect that the Sierra Leone campaign and industry calls to charge for water cannot be pure coincidence. Some see a cynical ploy to take advantage of charitable feeling for extra profit.
And many are determined to resist.
To charge for water would "be absolutely outrageous as far as I'm concerned," says Marinko Medic.
Doris Roitner calls the idea "unacceptable." Caroline Wehner, herself a waitress, says a free glass of water with an order should routinely be "part of good service in Vienna."
Admittedly, the water dispute takes a back burner even in smug Vienna to the debt crisis threatening Spain, Greece, Ireland, Portugal and other countries in the 17-nation zone using the euro.
But for now, prosperous Austria's involvement in the crisis is restricted to people fretting that their tax euros may be spent frivolously in helping bankroll risky bailouts, and there is a feeling of disconnect with Europe's less privileged. At 3.9 per cent, Austria's unemployment rate is the lowest in the EU and its economy continues to expand at a time of standstill or contraction in much of the rest of the continent.
All the more reason for interest in an issue close to the hearts and wallets of the Viennese. Much of the city lives from the hospitality industry, earning over 16 billion euros (nearly $20 billion) from tourists in 2010.
Its coffee-house culture — including tuxedo-clad waiters and that free glass of water — was born in the 17th century after the Turks introduced coffee to the Austrian capital. Almost as long-established is the free pitcher of water served with each carafe of young wine brought to wash down delicious al fresco tavern fare.
Few drinking and dining establishments in other EU countries with drinkable tap water put a price on it, and Vienna takes pride both in its water quality and its restaurant service. Asked recently about paying for tap water at city eateries, more than two-thirds of 3,096 respondents surveyed by the daily Kurier rejected the idea.
The charity running the Sierra Leone project says part of the idea is to "strengthen awareness for the incalculable value of clean water" in a city where taps are fed by pristine Alpine streams and rivers.
But participating restaurants keep half of the price of 2 euros per litre ($2.45 per quart). And prominent Viennese eatery and cafe owners have started to clamour for an end to free tap water, just as the Chamber of Commerce launched a poll of restaurateurs asking for their views on the matter. All of that has sharpened suspicions that eateries are really just out for a profit.
"People used to drink four mugs of beer, now they drink three and a glass of water," says Bernt Querfeld, who comes from a Vienna cafe dynasty and runs some of the city's most frequented establishments. "Water is free for now but I cannot tell you whether it will stay that way for long."
Proponents of charging for water deny that their calls are linked to the charity project. But critics are not convinced.
Vienna tourism director Norbert Kettner last week called for an end to the Sierra Leone campaign, describing it as "an attempt by certain gastronomes to reduce service using the excuse of a charity action."
"The good reputation of Destination Vienna is compromised," by such actions, Kettner said, describing the free glass of water "as a traditional service in Vienna's gastronomy."
Querfeld is not impressed, saying guests do not realize the extra costs — and work — that serving those free glasses generate.
"When I was a child, my father used to tell me: 'If you're thirsty go to the bathroom and drink the tap dry,'" he told Kurier, the Austrian daily.
"'But I don't want to see you bothering the waiters.'"
Associated Press writers across Europe contributed.