I guess 'dip out' here means 'get it out.' But what is the subtlety? How different is it from just 'get it out'? Is it saying you use a ladle to get the water out of the barrel?
My respect for water continued, as it remained a precious commodity. We purchased it from a vendor who transported his wares through the neighborhood by donkey, then we stored the water outside in a barrel. The family dipped it out sparingly for bathing, cleaning, making tea, cooking.
('Desert Flower' by Waris Dirie)