Analysis / Blood Bath

For the literal-minded, a full grown adult male human contains about 5 liters (1.32 gallons), less for women or children. Bathtubs of the sort found in homes and hotels are in the range of about 300-450 liters (about 80-120 gallons). To fill your bathtub (without accounting for the bather's volume) would therefore take 60 to 90 or so grown men. If you absolutely need to specify young (presumably virgin) women, add another 20% or so brings this number up to 72-108. Incomplete extraction of the blood volume and the absolute ponds that some bathers seem to use (for example, Lord Damaskinos in Blade II or Ronan in Guardians of the Galaxy) will naturally increase these requirements. A small rural village in medieval Hungary would seem to run out of virgins very quickly indeed.
http://tvtropes.org/pmwiki/pmwiki.php/Analysis/BloodBath