A wobble plate piston water pump for use in a pressure washer and driven by a driving source, the driving source being electric powered and having a power consumption of less than or equal to a 15 ampere draw at 120 volts or 220 volts or the driving source being gas powered and having an engine displacement of less than or equal to 250 cubic centimetres, characterised in that the water pump comprises: a pump body (12,13,14) defining five channels; a wobble plate disposed in the pump body (12,13,14) and having a rear side and a front side, the wobble plate being rotatable around a rotational axis via mechanical connection on the rear side to the driving source, the front side being inclined at an angle between 5 and 10 degrees perpendicular to the rotational axis and coupled to the rear side by four equally annularly spaced thrust bearings, the wobble plate comprising a pitch circle diameter defined by the thrust bearings; five equally annularly spaced pistons each having a proximate end and a distal end, each piston located in a respective one of the five channels and each having a spring retainer located on the proximate end, the spring retainer of each piston being biased to contact the front side of the wobble plate, the pistons being reciprocatable within the channel along an axis transverse to the rotational axis during rotation of the wobble plate, the pistons defining a pitch circle smaller than the wobble plate pitch circle; and a water passage defined by a water inlet and a water outlet each in selective fluid communication with one of the plurality of channels based on the phase of reciprocation of the respective piston for that channel, the water inlet providing low pressure water to the channel while the respective piston for that channel is moving away from the water inlet, and the water outlet receiving high pressure water from the channel while the piston is moving towards the water outlet. a pump body (12,13,14) defining five channels; a wobble plate disposed in the pump body (12,13,14) and having a rear side and a front side, the wobble plate being rotatable around a rotational axis via mechanical connection on the rear side to the driving source, the front side being inclined at an angle between 5 and 10 degrees perpendicular to the rotational axis and coupled to the rear side by four equally annularly spaced thrust bearings, the wobble plate comprising a pitch circle diameter defined by the thrust bearings; five equally annularly spaced pistons each having a proximate end and a distal end, each piston located in a respective one of the five channels and each having a spring retainer located on the proximate end, the spring retainer of each piston being biased to contact the front side of the wobble plate, the pistons being reciprocatable within the channel along an axis transverse to the rotational axis during rotation of the wobble plate, the pistons defining a pitch circle smaller than the wobble plate pitch circle; and a water passage defined by a water inlet and a water outlet each in selective fluid communication with one of the plurality of channels based on the phase of reciprocation of the respective piston for that channel, the water inlet providing low pressure water to the channel while the respective piston for that channel is moving away from the water inlet, and the water outlet receiving high pressure water from the channel while the piston is moving towards the water outlet.