Noun: low-water mark
- A line marking the lowest level reached
"The drought caused the river to recede to its low-water mark"
- An extreme state of adversity; the lowest point of anything
"The team's performance was at a low-water mark in the middle of the season";
- nadir
Derived forms: low-water marks
Type of: adversity, hard knocks [informal], hardship, water line, watermark