Limpid water and without chlorine odor; a vegetation which does not have anything to envy that which grows spontaneously in a lake and along banks of a river; a happy atmosphere which creates lives, the contact with nature and the feeling of return at the origins. Those are the characteristics of the biological swimming pools or natural swimming pools.

Filtration is carried out by the microfaune and the watery microflora which develops in the gravel and zeolites of the zone of regeneration. The watery plants, beyond having of an aesthetic function, absorb nitrogen and phosphorus dissolves in water and the submerged plants help to maintain water sufficiently oxygenated.

The natural swimming pool forms part completely of the landscape and has a function ornamentale even in period of winter.

The natural swimming pools exist in great number in the countries from where they are originating: Austria, Switzerland and Germany, where there are even public natural swimming pools. One estimates the number of natural swimming pools at 20.000 in Austria, 8.000 in Germany, 1.500 in Switzerland and of many in Belgium, Holland, Hungary, France, Russia, Italy. In Europe, one gradually appreciates the great advantages of this type of swimming pools.