The drawer and the trap want the same space
A vanity drawing can look generous until the basin waste, trap and supply connections are placed inside it. A conventional trap may occupy the centre of the upper drawer, forcing the cabinetmaker to cut around it or replace useful storage with a fixed panel.
That is why the plumbing layout should be resolved before fabrication. The cabinet should be designed around the actual basin and waste, not measured from a generic product image.
There are several ways to solve it
The drawer can be shaped around the services, the plumbing can be arranged to preserve more internal volume, or a manufacturer-approved space-saving connector can be used where the basin and system are compatible.
There is no universal best solution. A custom drawer, a bottle trap, a concealed installation element and a factory furniture system each have different requirements for access and future replacement.
Double vanities multiply the conflict
Two basins mean two wastes, two mixers and a more complicated set of service positions. If the centres are chosen only for visual symmetry, the plumbing may collide with the drawer grid or leave no useful storage in the middle.
The right elevation shows the finished floor, vanity, top, basin rims, mixer centres, mirror, lights and internal drawer divisions together. This is how the design team sees the conflicts before the cabinet is built.
Storage should be designed around real use
The question is not simply whether a drawer opens. It is whether the drawer still stores the items the household needs after the plumbing has taken its share of the cabinet.
A well-designed vanity makes the services accessible without sacrificing every useful drawer. That requires coordination between the basin supplier, plumber, cabinetmaker, countertop fabricator and installer.
See double vanity planning, or continue to the Durban bathroom renovation service.