^ This.

Used 4 x 1.4l bottles to store water in my ruck during field problems (military)

Carried a HDPE one for 6 years daily, running it through the washer with heated dry regularly… one day I dropped it without the top secured and it cracked.

They seal well so you can stow them in anything.

Maxpedition drop pouches fit them well if you ever need to secure it to a bike, backpack or belt.