Most of the work in a softener visit happens in the first hour. The last ten minutes are when you find out whether that work holds. Once the technician packs up, every setting, connection, and valve position becomes your problem, and the first sign of a mistake is often a puddle, a sour taste, or a control display that shows an error at two in the morning. A short walkthrough before the truck pulls away catches most of those problems while someone who can fix them is still standing in your utility room.
Ask for the settings out loud
Have the technician read the control head settings to you and write them on the service ticket. You want the water hardness setting, the regeneration time, the day or meter setting that controls how often the unit cycles, and the salt dose if the display shows it. Compare each number to what was agreed on the paperwork before the job started. If the ticket says one thing and the control head says another, fix it now and initial the change. A mismatch you accept at the door is one you will argue about later.
Watch one full regeneration
Ask the technician to start a manual regeneration while you stand there. Listen for the valve moving, watch the drain line for water flow, and confirm the unit moves through its cycle and returns to normal service without stalling. If the drain line sprays hard, gurgles, or does not flow at all, stop there and ask why. You do not need to understand every stage of the cycle. You only need to see that the cycle finishes and the unit comes back to service mode on its own.
Check every joint, then check again
Look at each fitting, valve connection, and drain connection while the unit is running and again a few minutes after it stops. A dry paper towel wrapped around a joint shows a slow drip faster than the eye does. Check the floor under the unit and under the brine tank, and look at the base of the brine tank where it meets the floor. Leaks that appear after the first cycle are common enough that a second look is worth the minute it takes.
Confirm the salt and the brine level
Ask who added the salt and whether the brine tank water level sits where the manufacturer's instructions say it should. If you are not sure what that level looks like, ask the technician to point to it on the tank. Ask how much salt is in the tank now and roughly when you will need to add more, so the first refill does not catch you off guard.
Set the bypass and show the shutoffs
Put the bypass valve in the position the manual calls for and have the technician show you which way it turns for bypass and which way it turns for normal service. Then find the main shutoff for the house, the shutoff for the softener, and the drain connection. Ask the technician to point to each one with you standing there. The first time something goes wrong, you should not be reading labels on a wet floor.
Get the next contact written down
Before you sign, ask for the service phone number, the email or portal address if there is one, and the date of the next maintenance visit if the plan includes one. Ask what the display error codes mean and have the technician explain the two or three most likely to appear in your first month. Write what they tell you on the ticket or in your service record.
If something looks wrong, do not sign yet
If a joint still drips, a cycle stalls, or a setting does not match the paperwork, do not sign the completion line. Ask the technician to note the open item on the ticket with a date and a plan to fix it. A written open item is far easier to enforce than a verbal promise made while the crew is already loading the van. Once everything checks out, sign, keep your copy, and file it with the rest of your softener paperwork.