Residential water filters, including sediment and activated carbon filters, may remove some of the manganese in our water but can't remove all of it. They may infact remove very litte. The reason is a large portion of the manganese can be dissolved in the water (particles less than 0.45 microns in size) or too small for a typical sediment filter to trap (particles less than 10 microns in size). This is why the Town plans to construct a greensand filter system.
A greensand filter is able to trap the larger particles and chemically react with the remaining manganese, drawing it out of the water through adsorption. Greensand filters are not typically found in a residential settings because the manganese trapped in the filter media periodically needs to be removed by backwashing or regeneration with chlorine and/or potassium permanganate.