Corrosion of pipes Is one of the most serious problems in the maintenance of water worlds. Corrosion is promoted not only by physical factors such as temperature, but also by electrochemical factors including concentration of soluble metal ions, chlorine ion, pH, DO and microorganisms. Corrosion products also affect corrosion rate. In this research, study results are summarized as follows ; 1) Corrosion test was performed for 4 weeks at $70^{circ}C$, pH 7.0 with specimens of 4 types of metal materials used as service pipes. Corrosion rate and S.E.M were analyzed. The results were showed that corrosion 1.ate of carbon steel pipe was 4.10~5.22 $mg/ extrm{cm}^2$ . week, galvanized steel pipe 0.98~1.34$mg/ extrm{cm}^2$. week, Copper pipe 0.02~0.04$mg/ extrm{cm}^2$. week, stainless steel pipe 0.05~ 0.10$mg/ extrm{cm}^2$ . week. 2) When corrosion rate was tested for tile types of pipes at pH 7 and both $25^{circ}C$ and $75^{circ}C$, avaerage corrosion rate for 6 weeks at $25^{circ}C$ Ivas 2.26$mg/ extrm{cm}^2$ . week in carbon steel pipe, 1.99$mg/ extrm{cm}^2$. week in galvanized steel pipe, 0.26 $mg/ extrm{cm}^2$. week in stainless steel pipe. At $87^{circ}C$, average corrosion rate for 4 weeks u.3s 4.56 $mg/ extrm{cm}^2$. week in carbon steel pipe,