Here's one on craigslist . . .. maybe more then you are expecting to pay, but maybe worth a call to make an offer ?  Otherwise, St Cloud has a water and sewer jobber, and they sell them (Granit ciy sewer or pipe ) something like that. http://minneapolis.craigslist.org/ank/tls/1850795974.html 

I have called gopher state one call, and had them locate the wires - with in 75 ft of the service. The guy said they weren't supposed to, but did it anyway. I filped him a few bucks - as it was very worth it for me. Then I GPS'd them . ..  .