Additional features include new SS appliances, recessed lighting, new 200 amp panel and updated electrical in kitchen, a French drain system, and 1 car garage w/ workshop.

Where does this plugged up deck drain exits or daylights? 

I would think you need to some serious landscaping to get the land pitched away from your house or install some trench drains to control the amount of water getting to your house.Adding concrete or building the house up 24" seems like it would be way too expensive to expect a decent

People will abuse it and shove stuff down the drain that clogs up the pipes to. 

However, you'll still have issues with seals on toilets, drains, dishwasher, etc.

Hi, We recently had water backup come up from our floor drains in the basement.

If the price point is going to drain your capital, you might want to consider cheaper markets.

Seems like a pretty large drain on your cash flow. 

If the damage was caused by a backup of sewers or drains or if your sump pump broke there could be coverage if you have the Water Backup coverage endorsement.If you have a flood policy there may be coverage for certain items in the basement. 

If the lines were replaced/updated at any time...great, but I bet the drains weren't, and the underground is crumbling, or will, or has been.5 - Plaster walls.