Toilet water has at least 2 very different meanings. Eau de Toilette (toilet water) is a perfume. It may be held in a perfume bottle or atomizer (sprayer). Water that is flushed from an actual toilet may be held in a septic tank or a cesspool.
The name for a lavatory water container is a toilet tank. It is a reservoir that holds the water needed for flushing the toilet.
Toilet tank
flask
A picnic hamper.
That could be a gas tank or a gas can...
Dewar flask
folder, envelope, box, briefcase, filing cabinet, a safe, ...
water closet
a bottle
A bidet is a toilet that sprays water for cleansing.
It's an old fashioned obsolete name for a toilet or lavatory.
A wooden barrel that holds water is commonly known as a water barrel or a water cask.