Washington state constitution
Article IV
Section 10

The legislature shall determine the number of justices of the peace to be elected and shall prescribe by law the powers, duties and jurisdiction of justices of the peace: Provided, That such jurisdiction granted by the legislature shall not trench upon the jurisdiction of superior or other courts of record, except that justices of the peace may be made police justices of incorporated cities and towns. Justices of the peace shall have original jurisdiction in cases where the demand or value of the property in controversy is less than three hundred dollars or such greater sum, not to exceed three thousand dollars or as otherwise determined by law, as shall be prescribed by the legislature. In incorporated cities or towns having more than five thousand inhabitants, the justices of the peace shall receive such salary as may be provided by law, and shall receive no fees for their own use.