Washington state law says in Title 49, Chapter 44, section 140[0]; Requiring assignment of employee's rights to inventions - Conditions. (1) A provision

Washington state law says in Title 49, Chapter 44, section 140[0]; Requiring assignment of employee's rights to inventions - Conditions. (1) A provision in an employment agreement which provides that an employee shall assign or offer to assign any of the employee's rights in an invention to the employer does not apply to an invention for which no equipment, supplies, facilities, or trade secret information of the employer was used and which was developed entirely on the employee's own time, unless (a) the invention relates (i) directly to the business of the employer, or (ii) to the employer's actual or demonstrably anticipated research or development, or (b) the invention results from any work performed by the employee for the employer. Any provision which purports to apply to such an invention is to that extent against the public policy of this state and is to that extent void and unenforceable. (2) An employer shall not require a provision made void and unenforceable by subsection (1) of this section as a condition of employment or continuing employment. (3) If an employment agreement entered into after September 1, 1979, contains a provision requiring the employee to assign any of the employee's rights in any invention to the employer, the employer must also, at the time the agreement is made, provide a written notification to the employee that the agreement does not apply to an invention for which no equipment, supplies, facility, or trade secret information of the employer was used and which was developed entirely on the employee's own time, unless (a) the invention relates (i) directly to the business of the employer, or (ii) to the employer's actual or demonstrably anticipated research or development, or (b) the invention results from any work preformed [performed] by the employee for the employer. Please note I have made another comment in reply to someone else's about California state law, you can search for it. [0] https://app.leg.wa.gov/RCW/default.aspx?cite=49.44.140 https://app.leg.wa.gov/RCW/default.aspx?cite=49.44.140