According to the World Health Organization, the following sources are not recommended as drinking water:

- Water from radiator circuits, hot water boilers (home heating systems)
- Water from the toilet bowl or cistern
- Water in waterbeds
- Water from swimming pools and spas

The chemicals and contaminants commonly found in pools are varied and mostly toxic: pH+, pH-, alkalinity adjustment (baking soda, muriatic acid, sodium bisulfate), calcium hardness increase, chlorine, bromide, biguanide, cyanuric acid, ammonia, bacteria and other pathogens, algae, insects and animal waste...

The presence and concentrations of these chemical contaminants depend on several factors, including the type of pool, the type and dosage of disinfectants used, the bather load, temperature and pH.

Although Black Berkey® purification elements have been rigorously tested by independent third-party laboratories for the removal or reduction of a wide range of contaminants (herbicides, heavy metals, chlorine, chloramine, pathogenic bacteria, parasites, pesticides, perfluorinated acid compounds, petroleum products pharmaceutical products, radiological products, trihalomethanes, viruses and volatile organic compounds...) and even though according to the data of these tests, the concentration of chlorine is reduced by more than 99.9%, we believe that it is not recommended to filter the pool water with Berkey® systems and to drink it for regular consumption.

This water may contain contaminants or chemicals other than those tested and for which we have no factual data as to their dangerousness.