IPA: /ˈreɪtˌpeɪər/
KK: /ˈreɪtˌpeɪər/
A person or organization that pays for services such as electricity, water, or gas, usually based on a set fee or rate.
As a ratepayer, she received a bill for her monthly electricity usage.
Ratepayer → It is formed from "rate" (from Old French *rate*, meaning a fixed charge or payment) and "payer" (from Old French *payer*, meaning to pay). A ratepayer is someone who pays a fixed charge or tax, typically for public services.
Think of someone who is responsible for making a 'payment' ('payer') for a 'fixed charge' ('rate') — that's what a ratepayer does.
No commonly confused words.