The cabinet under a bathroom sink shares the same awkward pipe layout as a kitchen sink, and tends to become a dumping ground for cleaning supplies and backstock without a deliberate system.
Measure around the plumbing
As with kitchen sinks, measure the usable space on either side of the pipes before buying any organizer, since a rectangular bin often won’t fit the irregular space.
Use a slide-out organizer
A pull-out tray or basket brings items stored at the back of the cabinet into full view, instead of requiring you to reach blindly past everything in front.
Add stackable bins for backstock
Extra toilet paper, tissues, and toiletry backstock stay more organized in stacked bins than loose on the cabinet floor.
Hang cleaning supplies with a tension rod
A tension rod near the top of the cabinet lets you hang spray bottles by the handle, freeing up the base of the cabinet for bins or boxes.
Line the cabinet floor
A removable liner or tray protects against the moisture and occasional leaks that are common in bathroom cabinets, and can be wiped clean or replaced easily.
Under-sink bathroom storage benefits from the same approach as under-sink kitchen storage — measure first, use vertical space, and keep the cabinet floor protected.