MILWAUKEE (CBS 58) -- Milwaukee DPW is getting ready for a big thaw that will likely cause an increase in broken water mains.

59 water main breaks were reported in Milwaukee in January which is down from 146 main breaks last year. In all of 2018, there were 517 main breaks and the five-year average is 538. 

Water mains are located under the street about six and a half feet down to prevent the frost line from reaching them too quickly. As soil around the mains shifts during freezing and thawing, extra pressure can cause them to break flooding the street and causing icy conditions. 

Half of the water main breaks each year happen in December, January, and February. The average cost of a broken water main is $2,400.