Slotted and unslotted basin wastes

By Tom Drake | 24th June 2024 | 3 min read

In this guide, we take you through the difference between slotted and unslotted basin wastes. The main factor determining whether you need a slotted or unslotted waste is whether your basin has an overflow.

Jump to:

• What is an overflow?
• Slotted wastes
• Unslotted wastes

Does your basin have an overflow?

Whether you need a slotted or unslotted waste will be determined by whether your basin has an overflow.

Slotted wastes

Slotted wastes are required if your basin has an overflow. They feature a slot which allows water that enters the overflow to drain away even when the plug is closed.

Unslotted wastes

If your basin doesn’t have an overflow, you’ll need an unslotted waste. Unslotted wastes are watertight and feature no slot for overflow water to drain away.

Does my basin need an overflow?

Whether you install a basin with or without an overflow will depend on personal preferences. Basin overflows will help prevent your bathroom flooding if the tap is left running, so they are popular with families.

Basins without an overflow will have a slightly smoother, more minimalist look than a basin with an overflow. However, as overflows are often very small, they won’t have a huge impact on the aesthetic of your basin.

What type of basins don’t have an overflow?

In general, a basin in a style that doesn't allow space for an overflow, such as a counter top basin, will be more likely to have no overflow. However, some countertop basins will feature an overflow and other types of basin may not.