To be eligible for the property tax exemption, you must own and occupy a primary residence in Washington and have a qualifying income. Once completed, use these instructions to submit your application. ​.A senior property tax exemption reduces the amount seniors 65 years of age or older have to pay in taxes on properties they own. You may be eligible if you have limited income and you're at least 61 years old in the year you apply for the exemption. Download and complete an application form, including the section on household income. The Treasurer's Office is the mailing agent of bills for the commonwealth.