This is to keep the foundation warranty in place. A foundation company did work and part of the post inspection/validation is to have a plumbing test and a sewer test. If there is a leak, no matter how many piers they put in, it will never be ok. So the hydrostatic test detected a sewer leak (which would explain a lot) and the foundation company's warranty is dependent on that test passing. Since it failed, I need to diagnose where the leak is, and then have it repaired. That's why I am looking for this service.