• Lilies are a common and beautiful feature of most natural pools.lillies in a pond image by Jorge Moro from Fotolia.com
  
  The natural swimming pool has been around for decades but has grown in popularity along with the environmental movement and new concern about common chemicals. Natural swimming pools forgo chemical cleaners in favor of a biological web that keeps pool water safe and clear. Proponents claim that chlorine in pools is bad for a swimmer's health and the environment, and owners enjoy how a natural pool can meditatively fit into any landscape. Natural swimming pools and ponds are popular in the mild climates throughout Central Europe, and are typically affordable for any homeowner eager to have a private swimming hole, but concerned about the environmental and health effects of a traditional pool.
  
  

Concept

• Natural swimming pools use modern technology to assist natural biological processes that filter a pool's water and keep it clean, crystal clear and safe for everyday swimming. Water is typically pumped through regeneration zones filled with aquatic plants that naturally trap bacteria and nutrients. Rocks or gravel piled in the regeneration zones also trap the small particles that would make any static, artificial pond murky within a matter of days. Natural swimming pools in Europe can attract local and migrating wildlife, particularly the endangered European tree frog.
  
  

By Country

• The modern natural swimming pools first took hold in Austria and Germany, countries where initiatives to keep urban dwellers connected to nature have a long history. The phenomenon has since spread throughout Western Europe into the United Kingdom, although climate restrictions have kept natural pools from making a bigger mark in Scandinavia. Most countries have local specialists, or at least traditional pool companies that are resellers for natural pool building materials and supplies.
  
  

Types of Pools

• Design needs and the existing property will dictate the type of natural pool that best fits a home. Although many homeowners desiring a chlorine-free pool initially believe they must install a pond, this is just one format that a natural swimming pool can take. Biological filter technology is available for any type of pool, including pools that look no different than a conventional pool. Natural design does not forfeit elegance and modern materials. Structural elements can be damaged by hard winter freezes, so ponds are suggested for Alpine areas and Northern Germany. Southern Europe can better support traditional designs, but may require additional maintenance.
  
  

Cost & Maintenance

• Generally, natural swimming pools have costs similar to, or somewhat greater than, conventional swimming pools. In addition to the carefully planned biological zones, natural pools require much of the same pumping machinery as conventional pools. Swimming ponds, which typically forgo expensive ornamental features, approach costs that are equal to the average cost of a typical home pool, while pools incorporating sophisticated materials, waterfalls and other personalized components quickly raise the price. Algae is a common problem that is much more pronounced in Southern Europe and along the sunny Mediterranean.