I am sorry that my fellow Realtors did not notice that the post specifically stated â€œprospective tenantâ€. Given that information, there is no lease in place to control the rent. A new tenant can agree to the asked for rent, negotiate a different level of rent or seek another rental opportunity. I donâ€™t think you need a lawyer or property manager to tell you that.
The way this question is written the answer would be yes. Not only that, the rentals in Denver are going up over 8% per year and it is common for rents to increase at the end of the current lease or when a new prospective tenant comes to rent the property. The rental market is very tight right now and the vacancy rate is less than 2% in most area.
As mentioned below, this is a legal question that must be referred to an attorney or perhaps a property manager managing the property. Especially given provisions of an in-place & enforceable lease (also mentioned below regarding the possibility of a lease transitioning into a month-to-month situation). But as John mentioned below, a landlord can ask whatever rent they want. The tenant or prospective tenant can refuse as well as negotiate. It's like any other business transaction in an open market (barring any governmental rent control, also mentioned below).
While licensed Realtors are not property managers, the issues surrounding your lease are governed by your lease. If you have a stated term at X per month, your rental rate cannot change unless you agree to do so in writing. If you are on a month to month lease, yes, the landlord can change your rental rate with notice.
The owner/landlord can ask whatever rent that he wants for his property subject to possible rent control or other specific laws that control rents. Do you have to agree to the amount? Only if you want to live there.