(1) The interest and penalties for delinquencies on property taxes must be waived by the county treasurer if the notice for these taxes due, as provided in RCW 84.56.050, was not sent to a taxpayer due to error by the county. Where waiver of interest and penalties has occurred, the full amount of interest and penalties must be reinstated if the taxpayer fails to pay the delinquent taxes within thirty days of receiving notice that the taxes are due. Each county treasurer must, subject to guidelines prepared by the department of revenue, establish administrative procedures to determine if taxpayers are eligible for this waiver.

(2) In addition to the waiver under subsection (1) of this section, the interest and penalties for delinquencies on property taxes must be waived by the county treasurer under the following circumstances:

(a) The taxpayer fails to make one payment under RCW 84.56.020 by the due date on the taxpayer's personal residence because of hardship caused by the death of the taxpayer's spouse if the taxpayer notifies the county treasurer of the hardship within sixty days of the tax due date; or

(b) The taxpayer fails to make one payment under RCW 84.56.020 by the due date on the taxpayer's parent's or stepparent's personal residence because of hardship caused by the death of the taxpayer's parent or stepparent if the taxpayer notifies the county treasurer of the hardship within sixty days of the tax due date.

(3) In addition to the waivers under subsections (1) and (2) of this section, the county treasurer, at his or her discretion, may waive interest and penalties for delinquencies on property taxes where the taxpayer paid an erroneous amount due to apparent taxpayer error and the taxpayer pays the delinquent taxes within thirty days of receiving notice that the taxes are due.

(4) Before allowing a hardship waiver under subsection (2) of this section, the county treasurer may require a copy of the death certificate along with an affidavit signed by the taxpayer.