The Different Types Of Bathroom Basin Waste | A Complete Guide

Were you visiting a friend and using their fancy ensuite bathroom where you encountered this fun basin waste? What was it? Did it make a cute clicking noise or perhaps flip back and forth? You want one for your bathroom renovation, but what was it called?

In this post, I’ll explain what a basin waste is, the difference between slotted and unslotted as well as look at the different styles available for your bathroom basin.

Let’s get into it!

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What Is A Basin Waste?

Your basin waste is the drain pipe connected to the bottom of your bathroom basin and sends wastewater to the main waste in the home. Most versions of basin waste have some kind of stopper to allow you to fill up the basin for handwashing clothes or taking a quick sponge bath. They also connect to the basin overflow.

The basin waste is sold as a single unit. It quickly connects to your home’s main waste using some sealant and a wrench.

Bathroom basin waste with overflow above

What Is A Basin Overflow?

The basin overflow prevents water from running over the rim of the basin and possibly damaging your floors, walls, and ceilings. It is generally located near the top of the basin on the back or side as a slot or a hole. The basin overflow connects directly to your basin waste. If the kids leave the tap running, the water can flow all day without flooding the bathroom.

Some basins in public locations do not have a waste that can close, so they may not have an overflow. If a tap leaks, the water will just run down the open waste.

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What Is A Slotted Basin Waste?

A slotted basin waste should be used with any kind of waste that features a plug or stopper. Nearly every residential bathroom basin will need a slotted basin waste. The slot is there to connect to the basin overflow. Water runs into the overflow and runs down into the slot, joining the waste pipe heading to the main waste.

Without a slotted basin waste, the basin overflow would just drip water onto the floor or inside the vanity cabinet.

What Is An Unslotted Basin Waste?

You would install an unslotted basin waste if you are using a basin just for handwashing that does not have an overflow or waste plug. It is a good option for motion-activated taps and a small basin that will always have an open drain. You often see this combination in pubs, malls, and school bathrooms.

Types Of Basin Waste:

Click Clack:

The Click Clack is rapidly becoming the most popular basin waste installed in homes around the UK. To close the waste, you simply press down on the button. When you want the water to drain away, press the button again and the waste opens. It gets its name from the “click-clack” noise it makes when opening or closing the waste. Sometimes they are called a push-button or sprung waste. It is a slotted waste to be used with a basin overflow.

Flip Top:

The flip-top has a centre disc at the top of the waste. Press one side of the disc and the waste will swivel down and close. Push the other side of the disc and it will turn and pop back up. Holes cut on the sides of the vertical portion of the waste ensure that it will drain even if the disc is in a sealed position. It is also a slotted basin waste that will work with your overflow.


pop up basin waste
Tap with pop-up basin waste (Rod behind tap)

If your bathroom was built before the turn of this century, it likely has a pop-up basin waste. Push down on the centre button to close the waste. Behind the taps, a rod with a knob at the top pops up. Press down on the rod to open the waste again. Because it has additional moving parts, the pop-up waste is falling out of favour with homeowners and plumbers. Still, it is affordable, and replacement parts are still widely available for this slotted basin waste.

Plug and Chain:

plug and chain bathroom
Plug and chain basin waste

Did you find an antique porcelain basin when a local school closed? If it has a small hole just to the side of the taps which has no apparent use, it probably used a plug and chain waste. A pin would be installed on the top of the basin. A chain ran from the pin to a rubber stopper. The stopper fits into the waste and serves to close the drain. The pin and chain prevented the loss of the stopper.

The drawback of the old plug and chain is that the waste had no means of catching hair and debris from going down the drain and causing a clog. Even most pop-up wastes have stems designed to capture clogs before they get deep down into the pipes. The plug and chain waste should also have a slotted design, but you can find unslotted versions designed for antique basins.

If you are going for an authentic basin look and function for your B&B, plug and chain wastes are still available.

Free Flow:

Finally, the free flow basin waste is the only unslotted basin waste on the market. It cannot be closed and is not intended to be used with a plug and chain. The top of the waste will have some kind of screen or trap to stop debris from getting down into the pipes, but it can be cleaned with a quick wipe. A free flow basin waste is intended for handwashing stations, not for a basin in which you might want to rinse out your clothes.

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Why Are There 2 Sizes Of Basin Waste?

Did you hit up the DIY store and find two different versions of basin wastes? That is because the same type of wastes can be used for your kitchen sink or bathtub. However, the larger sink and tub require a larger waste to drain water at a faster rate.

Your hand basin uses a 32mm basin waste. The water flow of the drain is matched to the maximum flow provided by your basin taps.

The kitchen and bath demand a 40mm waste. You will select a slotted or unslotted waste based on your fixture’s design. If you purchase a 40mm waste for your basin, it will not fit.

Ultimately, the size of the waste should match the taps. If you are going for an industrial bathroom look with oversized fixtures and taps, you need a waste large enough to handle the high flow of water coming down the spout. That may mean that you will opt for a basin originally designed for kitchen use. Consult with your plumber when thinking outside the box.

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Final Thoughts…

There you have it! Everything you need to know about the different types of bathroom basin wastes.

There’s no right or wrong option when it comes to selecting the style of basin waste you would like. However, make sure you select the correct type (slotted or unslotted) for your particular basin and if it has an overflow. As well as making sure it’s the correct size for your basin and it can handle the water flow from your taps.

So, which type of basin waste will you pick for your new bathroom?


Michael R

Michael is a KBB designer from the UK. He's been designing and project managing new Kitchen, Bedroom and Bathroom installations for over eight years now, and before that, he was an electrician and part of a KBB fitting team. He created The Bathroom Blueprint in early 2020.