What is a Natural Swimming Pool?

What is an NSP? NSPs, whether they are called swimming ponds, swim ponds, natural swimming pools, natural pools, organic pools or biological pools, are all based on the science of limnology and have four fundamental attributes.
 

1. The NSP is a contained vessel, i.e., the water in the NSP is contained and recirculated but there is no introduction of outside water such as from an underground spring, a stream or any other outside source, except for makeup water to replenish any water lost from evaporation or splash out.
    
2. The swimming zone of the NSP is always separated in some fashion from the biological filter. This means that any aquatic planting will not be adversely affected by the physical presence of swimmers.
    
3. There are no chemicals or other devices, such as UV, ozone generators, ionizers or salt systems, used to disinfect or sterilize the pool water. All clarifying and purifying of the pool water is performed entirely by natural biological processes.
    
4. The NSP is designed, engineered, permitted and constructed in conformance with applicable guidelines for a swimming pool.