I'm voting for the dead animal too, and if you've been noticing for a week or so, it's a small one, will hopefully 'dry up' quickly. Anything larger and you probably would be camped out in a hotel. Many years ago we had a 1920's house with a half basement, other half under the house was dirt/crawl space, and there were a couple of areas between the two under the house floor where something could squeeze in. Who knew. The 'scent' was wafting right out of the shelved closet in our bedroom. DH fled to his fathers farm and left me to deal with the pest company, who had told me they were prepared to find it, or they had some kind of odor killing spray they could inject into the wall if that's where it was determined to be. He found it, by pulling down ceiling insulation in the unfinished basement. Rat, along with several of those little packets of poison that people can toss out for exterminating them. Never did find which neighbor was using the rat bait... We sealed that area that could allow access, had a neighborhood meeting regarding kitchen compost, bird feeders, pet dishes, and everyone regularly cleaning up under any fruit trees - back then, there were a few neglected apple trees and 'ornamental' plum that were bearing fruit no one wanted and it was being left on the ground.

Fill the bathtub up 3/4 and try your tests again. I had a situation in my old house where a leak would expose itself after weight was put on the tub, because the house was really old and the underlayment had shifted a little. Doesn't take much of a gap to get leakage. Also, pointing a shower at a shower wall does not usually soak the whole wall, and does nothing to the front wall where the shower head is.

Loss about 3 to 5 inch of water every day, seems like the leak from bottom of the liner, any good method to detect the leak spot, thanks.

We own the dishwasher from hell! The appliance is five years old. In four years, we are on the second major flood... Our floors had to be replaced... TWICE! We will be getting rid of the scary dishwasher... But we have become totally paranoid of water damage from any appliance or plumbing device. Can any of you recommend a water detection system you like? Thanks!