In pressured irrigation systems, water flowing in pipes is stable from the point of view of the hydraulic and it gradually decrease through the pipe lines. In sprinkler irrigation systems, sprinkler head pressure through the pipe line is different due to friction and local losses formed in parts of the pipes between sequent sprinkler heads and the differences resulting from slope. Generally, sprinkler head pressure has a maximum level in the beginning of lateral pipe lines and a minimum level in the end of lateral pipe lines. The velocity of water flow in the pipe line, the diameter and length of the pipe and the friction loses formed as a result of roughness inside the pipe should be known for a good design. The easiest and fastest way is to make use of the values given in the tables or diagrams determined by the equation of Hazen-Williams. However, no data related to floppy polythene (PE) pipes with small diameter is available in the tables and diagrams mentioned. In this study, values relating to friction losses and pressures formed in 10, 20, 30, ..., 100 m through the pipe for the without slope in different velocity (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 m s(-1)) and water flow have been measured and it was found that connection between them using floppy PE pipes (6 bar) with small diameter (empty set20, 25, 32, 40 and 50) have been produced by some plastic companies in Turkey and particularly used in the irrigation systems in landscape areas. In conclusion, it was stated by the people who worked on the experiment that the parameters obtained could be used.