One of the goals of toilet redesign has been to reduce the quantity of water used to flush waste. Dual flush and other Water Sense technologies have addressed the amount of water used. But some companies are hoping to cut down on the amount of fresh water used in toilets, substituting so-called “gray water” for filling the tank.

Two options actually combine a small sink unit with the commode in a single sanitary appliance. Australians seem to be paying a lot of attention to water use and Aussie company Caroma’s dual flush toilet Profile Smart 305 takes water conservation to a new level: the unit comes equipped with a small sink incorporated into the tank module. The design allows for the hand washing water to drain directly into the tank for future flushes.

Another company in Spain, Roca, placed the basin to one side of the bowl, a nod to less awkward positioning for users of both sexes when it designed the W+W (stands for Washbasin + Watercloset) unit.  Either option is a space-saving design, which might make them the ideal option for a scaled-down extra lavatory in a loft area.

Another option using gray water from American AQUS Technologies involves a collection unit below the sink which pumps water into the toilet tank for a recycled use. This involves a more standard basin toilet set-up, but also reduces the under sink cabinet space. The benefit is that the sink doesn’t need to be directly next to the toilet, but can pump gray water through pipes to nearby locations

Though some of these may seem to be extreme, you may also be seeing the next new frontier in domestic water conservation.