Wash. Rev. Code § 41.20.160
Any person affected by this chapter who was a member of a police organization operated by a private enterprise which police organization shall be hereafter acquired before September 1, 1959, by a city of the first class as its police department as a matter of public convenience or necessity, where it is in the public interest to retain the trained personnel of such police organization, shall have added to his or her period of employment as computed under this chapter his or her period of service with said private enterprise, except that this shall apply only to those persons who are in the service of such police organization at the time of its acquisition by the city of the first class and who remain in the service of that city until this chapter shall become applicable to such persons.
No such person shall have added to his or her period of employment as computed under this chapter his or her period of service with said private enterprise unless he or she or a third party shall pay to the city his or her contribution for the period of such service with the private enterprise, or, if he or she shall be entitled to any private pension or retirement benefits as a result of such service with the private enterprise, unless he or she agrees at the time of his or her employment by the city to accept a reduction in the payment of any benefits payable under this chapter that are based in whole or in part on such added service by the amount of those private pension or retirement benefits received. The rate of such contribution shall be two percent of the wage or salary of such person during that added period of service with the private enterprise before midnight, June 8, 1955, and four and one-half percent of such wage or salary after midnight, June 8, 1955. Such contributions shall be paid into the police relief and pension fund and shall be held subject to the provisions of RCW 41.20.150, except that all such contributions shall be deemed to have been made after June 8, 1955. Such contributions may be invested in investments permitted under chapter 35.39 RCW and may be kept invested until required to meet payments of benefits to such persons.
The city may receive payments for these purposes from a third party and shall make from such payments contributions with respect to such prior service as may be necessary to enable the police relief and pension fund to assume its obligations.
RCW 41.20.160
Severability-1959 c 71: "If any provision of this act, or its application to any person or circumstance is held invalid, the remainder of the act, or the application of the provision to other persons or circumstances is not affected." [ 1959 c 71 s 2.]