Back on topic, saving water that would otherwise disappear down the plug hole is also very simple. If you use a washing up bowl you'll notice that it fills up alarmingly quickly just from catching the water used to wash hands, rinse out dish cloths and fill water glasses (for some reason many of us have a strange habit of filling a glass, emptying it and then filling it again to drink....for no apparent reason!). This water, if free of toxic, non-degradable products can be saved for up to 24 hours and used on the garden or on house plants. It is not recommend to store grey water (water used to wash dishes, bodies,etc) because of the anaerobic bacterial blooms which grow from the organic particles floating about in it. On the same premise you could also save the baby's bathwater.....just remove the baby first.
In the garden the most obvious water-saving measure is to install water butts to capture rain water when it's falling to use when its not. The key is to capture as much as you think you'll need to get you through the longest potential dry spell. This generally translates to: as much as possible. Anywhere you have a roof you have the potential to put in a gutter and down pipe, and therefore one or more butts. Multiple butts can be joined in series using a joining pipe just below the rim of each butt so that as the first one fills to the top it overflows via the pipe to fill the next one and so on. It makes sense to store water as high as you can so that you have enough pressure to use a hose if you need to, or at least get a good sized can or container under the tap.
If you're watering on a large scale you can think about water-saving irrigation methods such as drip-lines (pictured below) or seep-hoses which deliver water directly to the soil at the base of the plant and reduce water wasted through spillage and evaporation. These systems do need pressure, so will need to be fed by either the mains or a large, high water tank.
These are just a few things that we do here at Tawny Oaks, but I am constantly cheered by hearning about other creative systems and methods that people are using. Please share your own ideas!