Legal Question in Family Law in Washington

You can try, but without spending a lot of time consulting the statutes, I do not think you will prevail, unless you can show an independent contract whereby you both agreed to pay for these costs, and even then, I'd say the case is precarious.

This is why family law attorneys always say to get those custody and support orders entered into as soon as possible for unmarried parents, so as to ensure post secondary education is paid for by both parents where feasible.