In 1998, Washington voters approved state Initiative Measure No. 692, allowing a qualifying patient or designated provider to have a 60-day supply of medical cannabis, later defined as 24 ounces and 15 plants. Under the measure qualifying patients and caregivers within those limits are protected from arrest and prosecution, and a patient who exceeds those limits is entitled to a medical defense of medical necessity. Designated providers must be 18 years of age or older. 

Legal retail access for patients at dispensaries was not permitted under Washington law until voters approved I-502 authorizing an adult-use commercial cannabis program in 2012. However, Washington did allow patients participating in cooperatives to grow cannabis, and these provisions of the state’s medical cannabis laws remain in place today. Acknowledging the lack of insurance options available to subsidize the costs of medical cannabis, the state shields cannabis patients from state and local taxes applied to legal cannabis at retail establishments. 

In 2017, Washington passed SB 5131, which provided a slight improvement to Washington's medical access market. The bill allows qualifying medical card holders in the state database to purchase immature plants, clones, and seeds directly from licensed cultivators authorized by the state to conduct these activities. SB 5131 also implemented a few technical changes, including provisions related to consulting agreements, advertising restrictions, research, and qualifications for organic cannabis. 

In 2018, regulators released new packaging and labeling requirements, as well as the state’s first research license. In 2019, the state temporarily suspended the requirement that cannabis products be tested for heavy metal because there were no labs certified to do so. A lack of laboratory testing creates an enormous safety problem for patients. While there was only a temporary period where heavy metal testing was suspended, any time where legal products are untested and made available to patients is too long. 

The 2019 legislative session saw a suite of new medical cannabis laws designed to benefit the state’s registered patient population. Included in these measures was legislation exempting qualifying cannabis patients from in-person physical examinations in order to renew their annual registration, as well as a measure allowing patients to consume cannabis products on school grounds, school buses and at school events. The state also passed legislation to align Washington’s hemp program with the 2018 Farm Bill, which transitioned the national hemp pilot production program into a permanent program under the USDA.

In 2020, Washington maintained patient access during COVID by authorizing medical cannabis businesses to continue operating, and permitted preordering and curbside pickup.  The state already had provisions in place allowing patient evaluations to be conducted via telehealth.