Electrospinning is a process to generate nanofibrous nonwovens. With these nonwovens, many applications can be targeted, such as water filtration. In this paper, polyamide nanofibrous membranes are evaluated for their pore size, a key parameter in water filtration, and for their removal of microorganisms. To increase the removal efficiency to values exceeding the state of the art, innovative functionalization of the nanofibres is studied. The nanofibrous membranes are functionalized using a one step method. Different functionalization chemicals are investigated which are Ag nanoparticles and bactericides. Ag functionalized nanofibres are used as a reference medium to compare with a novel bactericide based functionalization system. It is seen that nanofibrous membranes functionalized with the bactericides exceed the normal removal efficiencies obtained by microfiltration membranes. Furthermore, knowledge is built up on how these bactericides are inserted in the nanofibres themselves.