Answer: In Oregon, month-to-month RV tenants can be evicted with a 30-day, no-cause notice during the first year of their tenancy. After the first year, the no-cause notice to a monthly tenant would need to be a 60-day notice. Use MHCO Form 43C for no-cause RV evictions, choosing either the 30-day or 60-day notice option, depending on the length of tenancy.
Caveat: Portland and Milwaukie both have ordinances requiring 90-day no-cause notices to all monthly tenants, regardless of how long they have been tenants. The City of Bend requires 90-day notices after the first year of tenancy. In addition, Portland requires landlords to make "relocation assistance" payments to tenants evicted for no-cause, ranging from $2,900 to $4,500 - although the applicability of this requirement to RV tenants is legally questionable. Bottom line: Consult an attorney if you have an RV park in any of these cities.
If you have any week-to-week RV tenants, they can be evicted with a 10-day, no-cause notice. This applies even in the municipalities mentioned above, which all provide exceptions for weekly tenants. However, remember that to have a valid "week-to-week" tenancy, you must meet these specific requirements: (1) Occupancy is charged on a weekly basis and is payable no less frequently than every seven days, (2) there is a written rental agreement defining the landlord's and tenant's rights and responsibilities, and (3) there are no fees or security deposits (other than applicant screening charges). If your weekly tenant arrangements do not meet these specific requirements, your tenants will be treated as month-to-month tenants under Oregon law.
If you happen to have any fixed-term RV tenants, you cannot evict them with a no-cause notice until the fixed-term ends. Before that, it would require a for-cause notice (i.e., for breaking a park rule or for not paying the rent).
Finally, there is also an exception under Oregon law for RV "vacation occupants." A "vacation occupant" is someone who: (1) Rents the RV space for vacation purposes only, not as a principal residence, (2) has a principal residence other than at the RV park, and (3) does not occupy the RV park for more than 45 days. You would need to have these facts documented in a written agreement. "Vacation occupants" are not "tenants" under Oregon law. They can be asked to leave without any eviction proceedings and the sheriff can be called to assist if necessary.
As usual, you should always seek the advice of a knowledgeable attorney if you are unsure whether you can or should issue a no-cause eviction notice.