Yes. Not only is it normal for a property owner/manager to require a deposit to secure a reservation, but it's the industry standard.

Typically, deposits range from 25-50% of the total cost of the rental, although this varies owner-by-owner. Since space is limited at their rentals, owners want to be sure that a renter is serious about a reservation prior to taking their property off the market during the time you requested.

Refund policies also vary owner-by-owner, so it is best to ask these questions upfront to avoid any confusion or misunderstandings down the road.