Characteristics of leak noise frequency was built through comparison analysis of collected acoustic signals from pipeline before and after leakage. Leakage was identified at 10 points, acoustic signals were collected at 14 water supply facilities(manhole, water valve, stop valve). Investigation time was set up from 11 PM to 5 AM in order to minimize effect of white noise caused by water usage, vehicle traffic, etc. Comparing results from characteristics of acoustic signals before and after leakage showed that signal strength became weaker after repaired pipeline from the full range of frequency bands, except for some uncertain data that include heavy noise. Frequency bands indicating strong signal strength were from 200 to 2,000 ㎐, with or without leakage. As a result of analysis based on pipe material, leakage-related frequency bands were identified from 300 to 2,000 ㎐ in case of galvanized steel pipe. On the other hand, frequency bands were related less than 1,200 ㎐ if leak occurred in stainless steel pipe. Frequency analysis result according to leak point, leak noise were related from 500 to 2,000 ㎐ in case of a leak in a straight pipe, frequency bands of leak noise in joints and junction had relevance to the range of 300 to 1,200 ㎐.