A negative supplemental tax bill is a separate bill that reflects assessment that is lower than the prior assessed value, a senior citizen’s transfer of Proposition 13 values, or other downward assessment and includes a refund check. A negative supplemental bill does not change your responsibility to pay all other property tax bills. However, the refund generated by a negative supplemental bill may be applied to any open bills for the same parcel. For more information please call 530-265-1285.