It depends what type of water ...

It depends what type of water you are treating and what the goals are. If you are dealing with groundwater, simple disinfection with chlorine is sufficient and the most cost-effective. Chlorine produces a residual in the water that will persist in distribution (it is desirable to aim for 0.2 mg/L throughout distribution). Surface water involves more costly treatment that requires much more operational knowledge. If surface water quality is low turbidity, there are some low-cost filtration options, such as cartridges that you can combine with chlorine disinfection.