Question: Is it absolutely necessary for a bathroom vanity to be made up of base cabinets?
Answer: The short answer is no. The long answer is that there are many different things to think about, if planning to do this. Find out what aspects to plan, if deciding to create this design.
The first thing to consider is that, generally speaking, the bathroom vanity is made up of base cabinets that provide most of the storage. If the bathroom includes a linen closet or cabinets in another location, some storage can probably be given up under the bathroom sink.
The lack of a base cabinet vanity in this photo shows that other arrangements can been made. The towel rack has been installed directly onto the counter. Typically a base cabinet vanity hides the plumbing of a sink. In this case special care for installing and concealing the pipes must be made.
If you decide to create a vanity without cabinets, you could consider adding wall shelves near the vanity. Extra storage has to be made available in this space. Toilet paper and fresh towels need a sensible place to live within this room. If you prefer to have these items concealed, perhaps you can find a place to fit in upper cabinets into the space. Upper cabinets could be added on top of the vanity in between two sinks. Their depth should not exceed twelve inches, as to keep the focal point balanced and not look top heavy.
Another option with a lack of cabinetry is the use of accessories that have storage capabilities. A basket full of towels, a stylish trunk for less attractive items, or a free-standing shelf for stylishly placed necessities (think cotton balls or soaps) are all wonderful additions to a simply styled bath. You may never even miss those under sink cabinets!
This particular design style is interesting and unexpected. Make sure careful planning goes into finding an alternate storage solution if you decide to give up the base cabinets in your bathroom vanity.