Europe is beating the pants off America when it comes to low-flow toilets. One pint of water per flush might be something to write home about on your side of the pond, but here in Europe, we've already seen our fair share of water-less urinals.

It turns out that the two main problems with not having water run around your loo after each pee are odor and blockage. Odor isn't as much of a problem as you would think, as specially designed traps can pretty much eliminate smells escaping. The other problem is blockage -- solids and salts accumulate in the traps of waterless urinals -- however, two litres of hot water a week poured down them is enough to ensure they stay clear.

Furthermore, the people at IFO have solutions for times when you just have to sit down. Some of their loos will clear the bowl using as little as two litres of water for less serious matters -- whilst effectively clearing the bowl using as little as four litres -- a shade over a U.S. gallon.

Furthermore, you can take water out of the equation altogether. This may seem a little extreme to the average U.S. consumer but might appeal to EcoGeeks -- the 'composting toilet' is now being carried at Home Depot. A compost toilet biologically digests waste to produce harmless compost as a waste product. If the balance of biological functions in a composting toilet is maintained at the correct levels then it should emit no odor at all!