When it rains a lot, our sump pump runs.  We previously (pre-geothermal) opted for $5,000 additional insurance coverage in case the sump pump fails or can't keep up.  I called our insurance agent today and we increased this coverage to account for the expensive geothermal units.  For us, the price per year was approximately $15 per $5,000 additional coverage (sounds reasonable to me).  I should have done this when the units were installed, but I didn't think of it until now.  From what I understand, if we had such an incident, we would have been left holding the bag for any costs exceeding the $5,000 limit.  I am mentioning this so others can check their coverage to make sure it is adequate for their needs.

Would the geothermal units be totaled if they were submerged 25%, 50%, 75%, 100%?  We have a split and a packaged unit in our unfinished basement.

As soon as water contacts energized wiring, that's all she wrote.

Off the top of my head compressor, heat exchangers and coils might survive, but the cost of changing out electrical parts and control boards and never being quite certain the thing is 100% reliable would militate in favor of a complete swap. Duct connections would need to be replaced as well - once fiberglass insulation gets wet, its pretty much shot as well.

Even though air source outdoor units are designed to be out in bad weather, they don't do well in floods, tending to be totaled out to my knowledge. That suggests indoor equipment would do even less well.

Others may disagree.

Might be wise to keep the units well off the floor or ground.

They are on 2" pads (approximately). I inquired about having them higher, but was told that could have vibration problems if higher (not sure if this makes sense or not.) If anyone has good ideas on raising them, feel free to volunteer them. It may help others reading this, or us when we replace our units.

I'd want as much elevation as the space allows, one or more redundant sump pumps and high water alarms, and possibly a mechanism to deenergize the all power to the units upon a rise in water. They are more likely to be repairable (no guarantees) if they aren't powered when submerged

Yeah, speaking of water and electricity...I think my Bard GHP could have been designed better. The electrical components (i.e. circuit boards, transformer, etc.) are housed in the bottom of the unit and since water runs downhill we all know what would happen next (Yeks, I better go check my homeowners policy).

Several years ago we lost our electricity when a huricane came up the coast. We watched the water level come up in our sump pumps over the next few hours. I must be just a bit higher than my neighbor as his basement flooded and mine didn't.

Later, I went down to the local home improvement center and bought a sump pump system that includes a main pump, a secondary pump, and a battery back up that is basically a car battery. I am not crazy about the quality, but I hope that between the two pumps and the battery I should be OK. I also have a little utility pump that has a water sensor in it.

In the past, we had a car in a train station parking lot when hurricane Floyd came through. 40+ cars were flooded out including one of ours with the water level 3" from the roof. We were hoping the insurance company would total the car since we were worried about future problems. Our insurance company decided to immediately total every car if the water level was over the dashboard. Talking about the geothermal unit possibly being salvageable after water damage reminded me of this situation. I don't think I'd want the old geothermal system fixed either.

Remember while you talk to your insurance company to ask for a "no gas appliance" discount.
Joe