That depends what its depth is in centimetres.
One that will hold the sink, faucet, and let you connect up the plumbing. 24" is normal.
When choosing a small undermount bathroom sink, consider features like size, material, shape, depth, and style. Size should fit your space, material should be durable and easy to clean, shape should complement your bathroom design, depth should be practical for your needs, and style should match your aesthetic preferences.
An average bathroom sink is 6-7 litres
Is the sink valve leaking in your kitchen or bathroom?
The amount of water needed to fill a sink depends on the sink's size and depth. On average, a bathroom sink can hold around 1-2 gallons of water, while a kitchen sink can hold around 8-10 gallons.
Sink, bathroom sink.
Is your bathroom sink cracked and in need of repair or replacement?
Is your bathroom sink leaking and in need of urgent fixing?
Additional shut off valve, below sink or in basement. Incomplete pipes not tied into bathroom sink line.
A typical bathroom sink uses around 1.5 to 2.5 gallons of water per minute when the faucet is running.
Snake your drains
If your bathroom sink pipe is leaking, it requires immediate repair.