RCW 28A.225.010 (Attendance mandatory – Age – Exceptions) provides: "(1) All parents in this state of any child eight years of age and under eighteen years of age shall cause such child to attend the public school of the district in which the child resides and such child shall have the responsibility to and therefore shall attend for the full time when such school may be in session unless: ..." The statute then lists out a series of exceptions. The statutes are here: http://apps.leg.wa.gov/RCW/default.aspx?cite=28A.225 .
Some school districts take nonattendance more seriously than other districts.
If you are wanting your child to attend school, you may want to contact the school to see what programs the school offers or references it can provide.
If you are being charged because your child is not attending school, you may want to review your facts and options with an attorney.