Emirates was forced to drop its initial plan to recycle the water used by its Airbus A380 fleet's on-board showers, rather carry up to 500kg (1,100lb) of additional water, after it fell foul of regulators.
The airline, which received its first A380 last week, put the 489-seater into service on 1 August between Dubai and New York.
All Emirates' three-class configured A380s will have two shower spa cubicles (which include lavatories) in the forward upper deck each side of the stairwell, ahead of the 14 first-class suites.
The airline's president Tim Clark says that shower systems on business aircraft use recycled water, and he has seen demonstrations of contaminated water being turned to drinking quality following normal and then ultra-violet filtration.
"The European regulators wouldn't allow that for an airline operation, and the shower idea was so important to us that we didn't fight it," he says.
Clark adds that Emirates chairman Sheikh Ahmed bin Saeed Al-Maktoum was "not keen" on the idea of using recycled water on the A380. However, Clark is hopeful that the regulators "will, in time, relax their stance and say that the quality is okay".
This would eliminate the need for the A380s to carry 25% more water. In the meantime "we'll be looking at ways of delivering the product using less water, but we will not compromise the facility", he says.
The shower concept has been in development for four years, and "technically was a big ask", says Clark. "Airbus was quite surprised, but we persuaded them that it was a good idea."
He describes the plumbing for the showers as "a masterpiece of engineering". They are fed from the central potable water tank located by the centre wingbox, which means that "it has to be pumped up two decks into the shower area and then heated by a special system installed under the seat in the shower cubicle".
Airbus offers the A380 as standard with six potable water tanks and a capacity of 1,700 litres (450USgal).
This can be increased to 2,270 litres through the addition of two auxiliary tanks.
The water is delivered "in a volume and velocity that will equal your shower at home", according to Clark. It is then drained back down to the water-waste tanks in the aft lower fuselage.
Emirates put its first 489-seat A380 into service on 1 August between Dubai and New York