Any designer who signs a board approved affirmation that they are not engaged in the practice as an on-site wastewater treatment system designer is eligible for inactive status. Those with inactive status are prohibited from any practice as an on-site wastewater treatment system designer as provided in chapter 18.210 RCW. A designer on inactive status may reinstate their license to active status by written request to the board and payment of any applicable fees. In the first year of reactivated practice the designer may be required by the board to collect an additional fifteen PDH.