A water treatment system includes a water inlet that intakes water to be treated, a high voltage (HV) electrode having a porous metal surface area in a range of between 0.1 cm2 and 5 cm2 in fluid communication with the water, such that the water flows through the porous metal surface area of the HV electrode, a ground electrode disposed across a gap from the HV electrode, in fluid communication with the water, a high voltage power supply electrically connected to the HV electrode for generating spark plasma or pulsed electric fields having a rise time equal to or less than 60 nanoseconds (ns) and an amplitude greater than or equal to 30 kV/cm across the gap, thereby producing treated water, and a water outlet that discharges the treated water.