This paper evaluates how upcoming changes in the Swedish tariff regulation could affect distribution system operators (DSOs), with focus on reinvestment planning. This is done by general analyses as well as by authentic calculation examples of a real power distribution system. The paper describes the Swedish tariff regulation with expected changes, provides a summary of changes in Swedish laws and regulation affecting DSOs between 1996 and 2016, describes how a DSO at local distribution level conduct their reinvestments, illustrates economic calculation examples and finally presents analyses and conclude the results. Analysis results presented show that the outcome from the regulation is sensitive towards relatively small changes in WACC and age structure. The tariff cap allowed will however be significantly reduced for all tested scenarios. A reinvestment rate of in average~10 % regarding meters and IT and ~2.5 % regarding all other categories could be a rough guideline to meet the new incentives, but that could differ depending on the actual age structure of the DSO.