Heavy rains contribute to muddy water. There is a solution to purifying this water using alum (aluminium sulfate) To a gallon of water about 2 ounces of powdered alum is added and briskly stirred. After seven or eight hours there will be a precipitate of dirt. Water then needs to be decanted, twice if necessary. This water though looks clean is not potable. It has to be sterilised and that can be done by boiling it.