How to save water in the home by Louise Jury - The Independent
Divert water from the roof or the shower into a rain harvester (like a water butt) and use it to flush the lavatory.
Install a "Hippo" (many water companies supply these free of charge) in the loo to reduce the amount of water in each flush. A brick or plastic bottle will also serve this purpose.
Don't leave taps running while brushing teeth or shaving.
Wash vegetables in a bowl and save the run-off to water plants. Water that contains washing-up liquid can kill aphids on roses.
Chill a bottle filled with tap water in the fridge - this saves running the tap until the water is cold.
Wait until you have a full load before using a washing machine or dishwasher. Use the minimum amount of water in kettles and saucepans.
Maintain your plumbing system; replace faulty washers to avoid leaking taps and avoid burst pipes by installing adequate insulation.
How to collect rainwater
"Dr Fowler thought water companies should respond by thinking of ways for water storage during extreme weather conditions, which could then be used during drier periods." BBC
Here are my own notes on collecting rainwater, it sounds simple, but I suspect there are some ways to improve the process:
Start with a large surface (such as a roof) - ideally with grooves or corrugations which catch the rain as it falls.
The surface should be sloped, so that the water runs down to one side.
Along that side, a gutter must be placed to concentrate the water into a single stream and carry it to the collection unit (ie. bucket/container/tank).
The collection unit must be placed so that the stream of water from the gutter runs into it.
If the water falls from a height, there will be a splashing issue, which can be countered with a funnel.
A funnel also helps reduce evaporation and noise, and keeps out most leaves and insects (tadpoles may grow inside the collection unit, however).
Once collected, there must be a way to draw the water from the collection unit - if it is simply a bucket, filling a bottle will become difficult as the water level falls (this can be countered, to some extent, by using smaller bottles as the level falls).
A collection unit with a tap at the base would be ideal.
Placing the collection unit in an elevated position will create pressure at the tap, which can be used to circulate the water along a pipe (eg. irrigation).
If more water is collected than needed, it can be stored - finally, a use for all those old plastic water bottles! However long-term storage is a problem, as green algae can grow in the bottles. This algae presumably eats the oxygen in the water and may reduce its usefulness - although if it is tipped on soil, it might end up as a light compost.
Ensure to allow for the eventuality of an overflow. Where will the water run if the collection unit fills? A decent setup might channel a large quantity of water in a downpour. Design the collection system so that a failure or blockage will not permit water to accumulate, particularly on the roof.
The ideal setup so far is thus a tiled or corrugated roof, with gutters, and a large tank with a funneled opening at the top and a tap at the bottom, sitting at least a metre off the ground, with good drainage at its base.