High rainfall conditions, especially in tropical countries, often cause flooding or inundation on road sections, especially urban roads. Puddles that do not enter or are hampered can cause damage to the road. This can be overcome by the inlet design of the road drainage channel that is suitable for the conditions in the field. By paying attention to the distance between inlets, dimensions, and inlet types adjusted to the rainwater discharge and the width of the existing road. Street Inlet is a hole on the sides of the road that serves to accommodate and distribute rainwater runoff along the road leading into the drainage channel. The research was carried out on a prototype that describes the condition of the highway with street inlet modifications such as conditions in the field. The method of analyzing surface runoff in the use of rational methods, inlet dimension analysis is used in the applicable hydraulic rules. The input data used are rainfall data, type of road, type of inlet street, rain runoff or inundation, drainage channel conditions, linear regression. This study discusses the performance of the road inlet to reduce inundation due to rain runoff (with a model of a rectangular inlet on the shoulder of the road). In the research carried out the type of inlet that will be used is the gutter inlet which has a horizontal opening. The results of this study indicate that the average rainfall intensity generated from alternative 1 rain testing with the first variation is 37.16 mm / hour, the second variation is 35.98 mm / hour and the third is 37.51 mm / hour. For alternative rain testing, the first 2 variations are 34.49 mm / hour, the second variation is 33.76 mm / hour and the third variation is 34.26 mm / hour. For the highest inundation volume occurs in 1 inlet hole with alternative rain 1 in the 24th minute which is 2.46 liters and the alternative rain 2 in the 30th minute is 1.32 liters. The highest peak runoff discharge value with alternative rain 1 is in 3 holes inlet 30 minutes that is 3.13 liters / minute while in alternative rain 2 peak runoff discharge in the 30th minute is 3.07 liters / minute. The average runoff coefficient generated from alternative 1 rain testing with the first variation is 0.73, the second variation is 0.79 and the third is 0.79. For alternative rain testing, the first 2 variations are 0.72, the second variation is 0.79 and the third variation is 0.83.