Ask the seller to remove the side panels so you can see the "guts".
Before shaking hands, ask the seller about the tub's pedigree: What to look for when buying a used hot tub? what to look for when buying a used hot tub
Buying a used hot tub is a journey that starts with the hunt for a bargain and ends with—hopefully—a long, warm soak. Ask the seller to remove the side panels
Look for "gentle weeping" from seals, mineral deposits (white crusty spots), or damp insulation. Leaks in fully insulated tubs are notoriously difficult and expensive to fix. Look for "gentle weeping" from seals, mineral deposits
. If it struggles to climb, the heater may be corroded or near the end of its life.
Lift it. A good cover should be light. If it feels like it weighs 200 pounds, it’s waterlogged and has lost its insulation value; you’ll need to factor in several hundred dollars for a replacement. The "Wet Test": Seeing it in Action