There are basically 3 ways. You declare your residency and your income to the government of CA. They could ask you for tax documents or permission to retrieve s

There are basically 3 ways. You declare your residency and your income to the government of CA. They could ask you for tax documents or permission to retrieve such. They could ask you for your pay-stubs or bank records of deposit. Alternatively credit reporting agencies have access to way more of your personal life than you might imagine including your income and one of the services they sell to business is looking up income. If you lie its incredibly trivial to put together the pieces and you have committed fraud by lying to obtain a benefit. Notably you aren't getting all your electricity for that figure just different fixed costs to go along with cost per kwh so there isn't that much benefit to lying to obtain. It's like risking jail time to obtain a relatively trivial amount of money.