It is not clear to me whether you were sued under the Family Car Doctrine. If you were, it is possible that you were found to have no legal responsibility. But it is possible to have legal responsibility for your sister driving your car even if you were not negligent in letter her drive.
In any event, there is a 3 year statute of limitations for negligence claims in Washington. If more than 3 years have elapsed since this crash occurred, you do not need to worry about being asked to pay for it.
You were found not liable which means you do not have to pay the judgement, whether or not your sister pays.
I am not in your State. I agree with the fine attorneys that responded. You should ask the attorney that went through the abritration process with you this question. If there was insurance, unless it is over the policy limits, the insurance company should pay on behalf of the insured(s).
I am an Arizona attorney. AVVO does not pay us for our responses. Simply because I responded to your question does not mean I am your attorney. In Arizona a non-lawyer is held to the same standards as an attorney so there are dangers to representing yourself. This is for informational purposes only and should not be considered as legal advice. If you require legal assistance an in depth discussion of your case is needed as there are many other issues to consider such as defenses, statute of limitations, etc.
Sign up to receive a 3-part series of useful information and advice about personal injury law.