PAUL can be used with rainwater, groundwater from wells or river water and maybe even other sources. However, the best source for raw water is rainwater, most likely from a pond. Usually, rainwater is free from:
– geologic load (e.g. arsenic, other heavy metals)
– industrial pollution
– pollution from farming (e.g. nitrate)
The solids that usually cause the brown color of most ponds will be removed perfectly by PAUL. Also consider the possibility for rainwater harvesting. Storage in a cistern, tank or simply a reservoir/lagoon/pond.