A softener install depends on a few details that have nothing to do with the tank itself. The drain line and the power outlet are the two most often rushed, and you can check both before the crew shows up. Walk the spot where the unit will sit and answer the questions below. Then put your answers in front of the installer and ask them to confirm each one on site.
Where the water goes when the unit regenerates
A softener sends its backwash and brine rinse down a drain line on a regular cycle. Ask where that discharge will end. Common answers are a floor drain, a standpipe, or a utility sink. Each needs an approved connection, usually with an air gap so the drain cannot siphon back into the unit. Ask the installer to show you the air gap or drain fitting, and ask whether it meets your local plumbing code. If they cannot name the code requirement, pause there rather than letting it slide.
Check the path too. A discharge hose that climbs high, bends sharply, or runs a long way to a distant drain can slow the flow during regeneration. Ask how the line will be run and whether the drain can handle the flow the unit produces during a cycle.
Power and the outlet
Most softeners plug into a standard outlet, and the control head needs to stay powered so it keeps its regeneration schedule. Look for an outlet within reach of the unit that is not on a switch someone might turn off by habit. Ask the installer whether the outlet is grounded and whether it is protected. If the outlet is not close enough, ask how the cord will be routed so it is not stretched, pinched, or lying in water.
The spot itself
Measure the floor space and height clearance for the main tank and the brine tank, and mark where the bypass valve and shutoff will sit. Confirm the floor is level and that the unit will not sit where a leak could go unnoticed for weeks. Ask which way the control head faces and whether you can read it without moving the tank.
What to confirm before the crew arrives
Give the installer one short list and ask them to confirm each item on site:
Where the drain discharges, and which fitting or air gap is used.
Whether the drain line meets local plumbing code, and who is responsible for that check.
Which outlet powers the unit, and how the cord is routed.
Where the bypass valve and shutoff sit, and that you can reach them without moving the tank.
Whether any water heater, pipe, or wall work is included in the price, or is your job.
Write the answers on the same paper as your quote. When the crew finishes, compare what they did against this list before you sign off. If you are still comparing companies, the award winners for greater St. Louis page is a place to start your shortlist. The drain and power questions apply to whichever installer you choose.