Monthly Renter Exemption:
Taken as a deduction on Line 2 of the tax report
Eligible exemptions:
Occupants renting space for more than 30 consecutive calendar days. The guest is eligible for a refund or credit for the 1st 30 days if they stay 31 days or longer without a break. Tax should no longer be charged starting day 31
People who rent a room on a monthly basis and pay all at once for the entire month (regardless of the number of days in such a month).

Source: https://www.portlandoregon.gov/revenue/article/415034#Registration