I was asked by a local mobile home park to look into an issues they were having. The asphalt was slightly collapsing several times right above where we know a 24" concrete storm sewer runs. After digging it up, I found the concrete to be in excellent condition, even the hub joint seems to be good. My question is for all of you underground utility contractors. What are the chances that there is a crack on the bottom half of the pipe(which happens to be under ground water)? What would the best way to locate any leaks be? Anything more then a quick repair would be beyond my experience but I would like to know just for future reference. Thanks.