RCW 62A.2-606: What constitutes acceptance of goods.

(1) Acceptance of goods occurs when the buyer: (a) After a reasonable opportunity to inspect the goods signifies to the seller that the goods are conforming or that he or she will take or retain them in spite of their nonconformity; or (b) Fails to make an effective rejection (RCW 62A.2-602 (1)), but such acceptance does not occur until the buyer has had a reasonable opportunity to inspect them; or (c) Does any act inconsistent with the seller's ownership; but if such act is wrongful as against the seller it is an acceptance only if ratified by him or her. (2) Acceptance of a part of any commercial unit is acceptance of that entire unit.