2/3 Rule
Water makes up 2/3rds of our total body mass. Men are about 60% water, whilst women are about 55 % water (as women have 5% extra fat). This is only occasionally clinically significant.
In your regular 70kg male, about 2/3rds of his body weight is water (roughly 42L).
In a 70kg woman, this would be about 38 L.
Most of our total body water is located within cells. (2/3rds, roughly 30 L in the intracellular compartment). 1/3 (roughly 12L) is extracellular (interstitial and plasma).
Majority of the water in the extracellular compartment is in the interstitial space (2/3rds, roughly 9L) (spaces such as pleural cavity and joint spaces).
The vascular compartment contains 1/3rd (roughly 3L) of extracellular fluid (plasma).
3L plasma + 2L red cells= Total blood volume (5L)