If you've been thinking about building a pool, you've probably heard all about the concrete, fiberglass, rebar and chlorine you'll need, not to mention the energy draining filtration system. But you might not have heard about another option that's less expensive, requires less maintenance and is environmentally friendly: a natural swimming pool.

You can build a beautiful natural swimming pool without any of the costly materials or dangerous chemicals mentioned above, for as little as $2,000, if you're willing to handle some of the work yourself. Your pool will be an attractive addition to your home and will create a habitat for many friendly, helpful frogs (they get rid of mosquitoes!) and other invertebrates.

One key to a natural swimming pool is the shape. When digging the pool, create sloping sides so that the earth doesn't collapse inward. The gradual incline allows you to avoid constructing steel framework and pouring concrete walls. In place of a mechanical filtration system, a border or designated area of aquatic plants naturally cleans and purifies the water.

If a more conventional pool shape is important, a good compromise is building a concrete pool structure while using the natural plant filtration system.

Beyond the shape, there are other integral elements to a natural pool:

Filters. A combination of submergent, emergent and floating plants suitable to your climate naturally filters the water, removing surplus nutrients as well as contaminants. When deciding the size of your pool, keep in mind that you'll need half of the surface area for these aquatic plants. Whether they're grouped at one end or spaced around the border, build a thin ridge to separate the swimming area from your natural filtration system.