Not my current house but previous one. 15 days before we gave over possession, there must have been a loud bang or something that scared the dog about 15 minutes before I woke up, he climbed onto the toilet and turned on the bidet and flooded the lower floor.
That was damn expensive to fix properly for the next people.
Not damage but the most entertaining, terrifying, and educational event - I made a mango soda, fermented it with some ginger beer and it was lazy getting fizzy so I bottled, refrigerated and promptly forgot about it. Found it a few weeks later and figured since it wasn't fizzy ok to open.
Mango soda on the floor, walls, ceiling of three adjacent rooms. It exploded up but did not break the glass bottle. The second one I opened outside facing away from me and got to taste the small amount that remained in the bottle - probably the best drink I have ever made, all lost due to my negligence.
That fried the circuits of 1/3 of the house. Some amateur electrician tied in several new circuits into the same kitchen breaker. They used undergauged wire on top of it.
Cost us $6k to fix and that was a hell of a deal from some Covid - unemployed union electricians. They put in 3 breakers where there was one before. The electrician had a hell of a time tracking where all the lines came from. That included a 3ft fireball shooter ng out of the wall because a line was love when it shouldn't have been.
My sister burned her apartment down by leaving a portable battery bank plugged in and charging. Luckily the reason she wasn't home at the time of the fire was because she was bringing the cat to a cat sitter, or else the cat would've been cooked too.
Be careful with portable battery banks folks! Don't leave them unattended!
My nephew (it was my own damn fault for leaving the equipment set up because I was halfway done with a project) siphoned 55 gallons of water from an aquarium I was building into the carpet.
And that's the story of how I learned to do flooring and replaced the carpet in my home office with linoleum so that the next time something like that happens it's non issue.
60 year old house. They used to use this stuff called "no corrode" pipe for sewage. It was made of tar and straw and had around a 60 year service life. Mine finally collapsed, backed up and caused $30k of damage to my basement + 25k cost to dig up my back yard to replace it.
The ceiling caving over the dining room was pretty bad. Right below my childhood bedroom too, so I had nightmares for a while.
Nothing too wild happened at my current place besides a pipe leaking while I was away for work. Landlord fixed the pipe but didn't clean up the water. Came home after a month to the saddest kitchen you ever saw
the old owners of my home neglected to get the the eves-troughs fixed (they were shitty landlords), it cost me about 10K for the replacement which will last 20+yrs. the leaking water ruined every window frame in the house, and cost us about 50K to repair that damage. replacing those windows also like halved our heating/cooling bills (and made the upper floors comfortable to exist in). Luckily we got a nice interest free government loan because it's greenifying our home.
they had all kinds of other landlord specials, like pouring concrete (not levelled right) down the basement drain and making the stairs to the attic out of plywood. fuck landlords. Did I mention they made over 400k on the appreciation of the house and were probably making 2-3K more per month than their mortgage from renting.
Shortly after we moved in, someone was taking a shower in our second-floor bathroom, the bottom of the shower cracked, and they didn't notice. End result was an entire shower's worth of water draining out the bottom of the shower, flowing about 10 feet inside the first-floor ceiling, draining down through the hole from a light fixture, across the kitchen floor, down through the kitchen floor into the basement ceiling, soaking into a bunch of exposed insulation, and making that insulation collapse onto the (concrete) basement floor.