Original sentence: Filtration (such as reverse osmosis or ultrafiltration) may remove pathogens which may be present in rainwater (such as cryptosporidium and giardia), or for chemical contamination in some areas.If rainwater is used for drinking, it is often filtered first.Maintenance includes checking roofs and rain gutters for vegetation and debris, maintaining screens around the tank, and occasionally desludging (removing sediment by draining and cleaning the tank of algae and other contaminants).Rainwater is generally fit to drink if it smells, tastes and looks fine; However some pathogens, chemical contamination and sub-micron suspended metal may produce neither smell, taste and not be visible to the eye.Rainwater tanks may be constructed from materials such as plastic (polyethylene), concrete, and galvanized steel, as well as fibreglass which is rust and chemical-resistant.Standard Methods for the Examination of Water and Wastewater (standardmethods
Edited sentence: Filters may remove pathogens which may be present in rainwater (such as cryptosporidium and giardia), or for chemical contamination in some areas.If water is used for drinking, it is usually filtered first.Maintenance includes checking roofs and rain gutters for vegetation and debris, maintaining screens around the tank, and occasionally desludging (removing sediment by draining and cleaning the tank).Rainwater is generally fit to drink if it smells, tastes and looks fine.Rainwater tanks are constructed from materials such as plastic (polyethylene), concrete, and galvanized steel, as well as fibreglass which is rust and chemical-resistant