Couldn't have been much worse than the rat water I had to deal with last week.

I had an extra trash can right outside my garage where the lid blew off before the last winter and I hadn't noticed. Naturally it filled with water once the snow melted. Last week I was digging around in that corner of the garage and smelled a smell, and found 3 massive (12" long before tail and probably 6" wide) rats that had gone in for water and didn't make it out. No clue how long they'd been in there, but I'm assuming quite a while based on the smell. I scooped them and some other trash out with a pitchfork. This water was straight rancid. Thankfully the was a portajohn a couple houses down for the house they're building, so I put it in there (I'm not about to dump that anywhere near my or my neighbors' houses). I felt real bad for the turd burglar that came to empty that.