Washington Revised Code Title 4. Civil Procedure § 4.22.060. Effect of settlement agreement

(1) A party prior to entering into a release, covenant not to sue, covenant not to enforce judgment, or similar agreement with a claimant shall give five days' written notice of such intent to all other parties and the court. The court may for good cause authorize a shorter notice period. The notice shall contain a copy of the proposed agreement. A hearing shall be held on the issue of the reasonableness of the amount to be paid with all parties afforded an opportunity to present evidence. A determination by the court that the amount to be paid is reasonable must be secured. If an agreement was entered into prior to the filing of the action, a hearing on the issue of the reasonableness of the amount paid at the time it was entered into may be held at any time prior to final judgment upon motion of a party.

The burden of proof regarding the reasonableness of the settlement offer shall be on the party requesting the settlement.

(2) A release, covenant not to sue, covenant not to enforce judgment, or similar agreement entered into by a claimant and a person liable discharges that person from all liability for contribution, but it does not discharge any other persons liable upon the same claim unless it so provides. However, the claim of the releasing person against other persons is reduced by the amount paid pursuant to the agreement unless the amount paid was unreasonable at the time of the agreement in which case the claim shall be reduced by an amount determined by the court to be reasonable.

(3) A determination that the amount paid for a release, covenant not to sue, covenant not to enforce judgment, or similar agreement was unreasonable shall not affect the validity of the agreement between the released and releasing persons nor shall any adjustment be made in the amount paid between the parties to the agreement.