An initial water gravity test determined that I have a sewer leak beneath my slab foundation after having piers installed to jack-up the foundation. Bids for finding the actual leak are confusing as plumbers use different methods. Some use the video & camera inspections, others use "drag test balls" system. Both are expensive. The initial leak test showed we are losing 12" per 10 minutes. Most assume that the jacking-up process broke the sewer pipe. My Texas insurance just renewed and this is no longer a covered expense. Any suggestions on how to select a plumbing contractor for finding my leak? Thanks for any help.