The right to exhibit the property is governed by RCW 59.18.150. The landlord has the right to exhibit the property to potential buyers.
I have pasted the relevant sections of the statute below:
Landlord's right of entry -- Purposes -- Searches by fire officials -- Conditions.
(1) The tenant shall not unreasonably withhold consent to the landlord to enter into the dwelling unit in order to inspect the premises, make necessary or agreed repairs, alterations, or improvements, supply necessary or agreed services, or exhibit the dwelling unit to prospective or actual purchasers, mortgagees, tenants, workers, or contractors.
(5) The landlord shall not abuse the right of access or use it to harass the tenant. Except in the case of emergency or if it is impracticable to do so, the landlord shall give the tenant at least two days' notice of his or her intent to enter and shall enter only at reasonable times. The tenant shall not unreasonably withhold consent to the landlord to enter the dwelling unit at a specified time where the landlord has given at least one day's notice of intent to enter to exhibit the dwelling unit to prospective or actual purchasers or tenants. A landlord shall not unreasonably interfere with a tenant's enjoyment of the rented dwelling unit by excessively exhibiting the dwelling unit.
(6) The landlord has no other right of access except by court order, arbitrator or by consent of the tenant.
(7) A landlord or tenant who continues to violate the rights of the tenant or landlord with respect to the duties imposed on the other as set forth in this section after being served with one written notification alleging in good faith violations of this section listing the date and time of the violation shall be liable for up to one hundred dollars for each violation after receipt of the notice. The prevailing landlord or tenant may recover costs of the suit or arbitration under this section, and may also recover reasonable attorneys' fees.
Doesn't seem fair. When you rent the property, you are given the 'exclusive' possession and use of that property...EXCEPT that the landlord has the right to inspect or access in case of emergency to preserve or save the property OR to show the property to a perspective renter or buyer. They must give you reasonable advance notice usually defined as 24 hour notice.
I assume you have a written rental agreement. That agreement will spell out the terms that allow the landlord or their agents access to the house and notice required.
Legal-yes.....FAIR only if you know about it.