This bill aims to expand eligibility for the working families' tax credit in Washington State to include all individuals aged 18 and older. It amends existing law to redefine "eligible low-income person" to include those who meet specific criteria, such as filing a federal income tax return and being a Washington resident. Notably, it allows individuals who do not meet the age requirement of the federal tax credit but are at least 18 years old by the end of the prior federal tax year to qualify. The bill also establishes a new refund structure based on the number of qualifying children, with amounts set to increase annually based on inflation.

Additionally, the bill includes provisions for the administration of the tax credit, ensuring privacy for applicants and outlining the application process. It mandates a review of the tax credit's effectiveness every ten years, with a potential expiration if it is found not to provide meaningful financial relief. The act is set to take effect on January 1, 2024, and emphasizes the importance of providing tax relief to low-income and middle-income working families to enhance their economic security.