Brewery water filtration often involves incoming mains or borehole water typically being filtered via an RO system for brewing liquor production and boiler feed for large commercial sites. Often incoming water for large breweries comes from ground or surface water sources meaning there are often unwanted elements that RO is used to remove. RO is preceded by carbon cartridges to remove chlorine and other chemicals, which could affect the RO membranes and the taste of the beer.