Müller work vehicles of the company Vodovod 0sijek d.o.o are intended for rising and cleaning of sewers and pits, emptying of pits and pools, removal of sewage sludge, sludge treatment and industrial cleaning or for collecting and transporting liquid or stallion waste. Older models are fitted with Mercedes 2636 Actros diesel engines with automatic transmission, and newer models have MAN THS 26440 diesel engine with manual transmission. Maintenance of these vehicles is a technological and organizational process that is carried out in the conditions of defined competence, technical equipment and available resources with the aim of keeping them in good condition for as long as possible, ir returning from faulty to correct condition. This process is extremely stochastic. The economic justification for maintaining Müller vehicle is conditioned by the complexity of these modern means – the high price – by restoring working capacity, the purchase of a new vehicle is delayed. If one wants to save in their lifetime then this should first of all bed in the process of maintenance and exploitation. Efficiency is the justification of the funds invested and depends on what this technical system provide sin relation to the set requirements. The reliability of work vehicles is the ability to work without failure and depends primarily on the design features of the system and its elements (for certain weather conditions and certain working hours). The Müller vehicle operating system consists of a number of elements necessary for quality work: superstructure, auxiliary drive, PTO shaft, drive, drive shaft bearings, belt drive, vacuum pump, sediment tank, hydraulic wedge seal, water tank, high – pressure water pump – three piston pump, hight – pressure hose winch, sewer cleaning nozzle, flushing gun, control cabinet and hydraulic equipment. Good maintenance reduces operating costs and extends vehicle life. Müller vehicle maintenance should be combined, ie preventive and corrective. Preventive vehicle maintenance is carried out after certain time intervals or kilometers traveled and serves to prevent possible breakdowns on the vehicle and avoid potential accidents. Corrective vehicle maintenance is performed after any malfunction to repair any damage to the vehicle that has occurred. In addition, good maintenance requires motivated and professional staff, as well as a well – equipped workshop.