'Chargeable': Where else, besides Singapore, is this word commonly used in this particular context?

Solution 1:

It has a legalese/bureaucratese flavour to it but it is used in the UK. Some examples:

• Law: Taxation of Chargeable Gains Act 1992
• Hotel rules: On-site parking is chargeable at...
• "cleaning is chargeable against the deposit"
• "costs are chargeable against the debtor" (certainly this one is also US)

So for your follow-up: yes you'd be understood, but you'd sound like a pompous jobsworth.

Solution 2:

The UK would say "taxable income", if you are talking about income on which tax must be paid. Chargeable does not sound like that to me, but like something else, like deductible expenses. On the other hand, we would all understand about the chargeable green tea.