If the board fails to cause any bonds to be paid when due or to promptly collect any assessments when due, the owner of any of the bonds may proceed in his or her own name to collect the assessments and foreclose the lien thereof in any court of competent jurisdiction and shall recover in addition to the amount of the bonds outstanding in his or her name, interest thereon at five percent per annum, together with the costs of suit, including a reasonable attorney's fee to be fixed by the court. Any number of owners of bonds for any single project may join as plaintiffs and any number of the owners of property upon which the assessments are liens may be joined as defendants in the same suit.
RCW 36.88.250