2023 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2022 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2020 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2019 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2018 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2016 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2015 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2014 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2013 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date

2009 Washington Code 18.106.080 – Persons engaged in plumbing business or trade on effective date