Abstract: Plumbing snakes, in-line carriers for sondes, and techniques for using the same are disclosed. Some example in-line sonde carriers may include proximal couplings for releasably connecting to plumbing snakes; elongated sonde carrying sections; distal couplings mounted to the sonde carrying sections; tools including tool couplings configured to releasably engage the distal couplings of the sonde carrying sections; and sonde tether assemblies, including retainers shaped to be received and captured within the proximal couplings, elongated, flexible tethers coupled to and extending distally from the retainers, and sondes coupled to and extending distally from the tethers. In some example embodiments, the tethers and the sondes of the sonde tether assemblies may be received within the sonde carrying sections via insertion through axial through-passages of the proximal couplings.