Most of the attention in an installation goes to the parts that are hard to undo: the cut pipe, the drain route, the electrical work. The final hour gets less attention, yet it is when you find out whether the system does what the quote promised. A startup walkthrough lets you see the unit running under real water pressure with the installer still on site. Once the truck leaves, every small problem becomes a phone call and a scheduling question.
Ask for the walkthrough before the first gallon moves
Tell the crew at the start of the day that you want to be present for startup and that you want a walkthrough at the end. Ask who will open the water, who will set the controls, and who will check the fittings once pressure returns. If the installer plans to start the system and leave, settle that now rather than after the fact.
Check the bypass before you trust the outlet
Find the bypass valve and confirm its position at the end of the job. Ask the installer to show you which position sends treated water to the house, which sends untreated water, and which is for servicing. Have them move the handle while you watch the outlet taps change. Confirm the valve sits in the position the installer intends you to leave it, and write that position down somewhere you will find it again.
Watch every joint once pressure returns
After water is back in the lines, walk the full length of the new piping with a dry paper towel and a flashlight. Check each fitting, union, and valve body, including the ones that are hard to see from the front. Moisture on the towel or a bead of water on a joint is a leak, even if it is slow. Ask the installer to tighten or re-seat anything that shows moisture before they leave, and ask them to recheck it after the system has run for a while.
Purge the air and confirm the drain
Air trapped in the lines can make taps spit or sound loud for a time, and it can make a new unit look faulty when it is not. Open a cold tap at the far end of the house until the flow runs steady, then do the same at a hot tap if the system serves hot water. Ask the installer to show you where the drain line discharges and how the end is positioned so it cannot siphon back. Ask when the first scheduled regeneration or flush will run and how you will know it finished correctly.
Get the settings on paper
Before the crew packs up, ask for the control settings in writing. For a unit with a programmable controller, that means the capacity or hardness setting the installer entered, the regeneration time, the clock, and any options turned on or off. You should also get the model and serial numbers, the installation date as the installer records it, and the name and phone number for startup problems. Keep this sheet with the rest of your paperwork.
Learn the three controls you will touch
You do not need to become an expert, but you should be able to do three things without help: shut the water off to the unit, move the bypass to its service position, and read the display well enough to tell whether it is in a regeneration cycle. Ask the installer to have you perform each one while they watch. If any step is unclear, ask for a short written note or a photo of the controls with the labels marked.
What to look for before you accept the job as done
When you are judging whether a provider finished well, compare what you saw against the original quote and the work order. Did the installer leave the system in the bypass position you agreed on? Did they test the fittings under pressure and tell you what they found? Did they hand over the settings and a clear contact path for problems? A provider who does these things without being asked is leaving you a working record. A provider who skips them is leaving you to find out later. If you are still choosing a provider, the directory lists the companies we cover, and our methodology page explains how providers are reviewed.