Now, a new idea has been put forward which will utilize areas which have no other obvious commercial potential. These are the ponds, small lakes, disused docks and other areas of water, many of which can be found near, or even in the suburbs of big towns. A new style of construction has been designed which will provide a house for less than half the cost of the conventional building. The main saving is, of course, the land, because the new houses will float on water. There will be no need for foundations; instead the house will be built on a frame made of steel which is expected to cost about ￡ 5 000. Above this the builders will make a house with two, three or four bedrooms and all the usual modern conveniences, as well as a roof garden. Each house will be joined to the main services supplying water, gas and electricity and they will have a vacuum sewage disposal(真空污水处理) system. All the service links will have enough flexibility to allow for small differences in the water level caused by wet and dry periods of weather.