Your landlord must either provide your full deposit, or an itemized list of deductions, within 14 days. That means mailed by 14 days. If the landlord fails to do so, she is barred from presenting any excuses if you take her to small claims court.
The landlord may use a defense that there were circumstances out of her control which prevented compliance with the rule.
Check out RCW 59.18.280 at: http://apps.leg.wa.gov/RCW/default.aspx?Cite=59.18.280
There are neighborhood legal clinics in some areas of Washington. A local lawyer may be able to help you through the small claims process (though not represent you in court) for little or no fee. Good luck.
Mr. Ackley did a nice job answering this. As a closer resource, I've written a couple of Legal Guides on this website about taking your landlord to small claims to recover your deposit.
Hope this helps- Elizabeth Powell