I know that Internachi standards of practice does not inspect water softeners. But my State Standards of Practice in the Plumbing Inspection sate:
2. An inspection of the plumbing system must include, without limitation:
(b) The operation of all plumbing fixtures and a visual inspection of all readily accessible components of the plumbing system;
Question: Should I consider a Water Softener a Plumbing Fixture or a Component of the plumbing system?
In NV, I would identify its presence, but disclaim it in my PIA.
Example:
INSPECTION DOES NOT INCLUDE – Negotiating issues with the builder/owner/contractor; sewer lines and/or onsite waste disposal systems; water softeners; shower pans, over-flow drains; identification of Chinese drywall; low voltage electrical systems; backup generators, data and communications systems or other ancillary wiring that is not part of the primary electrical distribution system, lightening arrestors; any timing systems; water purification systems; well systems; …
It appears his question was should he operate /turn on a water softner to see if it works for example if a customer has asked him to do so and what would the best answer to give customer for not doing so
I would consider it an appliance over a fixture. I would identify it and do a visual inspection as a courtesy but have it disclaimed in your agreement as Joe stated.
PLUMBING APPLIANCE. Water-connected or drain-connected devices intended to perform a special function. These devices have their operation or control dependent on one or more energized components, such as motors, controls, or heating elements. Such devices are manually adjusted or controlled by the owner or operator, or are operated automatically through one or more of the following actions: a time cycle, a temperature range, a pressure range, a measured volume or weight.
I would think water softeners are like sprinkler systems, not really a fixture but more of a add-on. Check it for leaks, hazards, etc. and move on. If client has further questions, because of the wide range of system types and controls I would recommend they consult with a specialist in that field to explain the operation of the system to them.