Plumbing Kitchen Sink Waste & Trap

Here's a step by step guide on how I fitted the kitchen sink waste pipe and trap in my utility. It also includes a trap connected to a washing machine hose.

I recently cut a hole in my utility kitchen worktop as part of my latest YouTube series. However, after plumbing up my new tap, I then needed to learn how to install the kitchen sink waste and trap.

I also talk you through adding my washing machine hose which is slightly further away.

This means my washing machine waste and sink waste are hooked up and drain in the same place. Or, you could bore another hole through the wall, which I didn't want to do.

How to Attach The Kitchen Sink Waste

When you buy a new sink, it usually comes with a kitchen sink waste. So, each fitting may vary slightly, including the gasket, which I'll show you. This is an Astracast sink purchased from Wickes.

First, just for demonstration purposes, here's the bottom drain section. The pipe ideally should aim towards the overflow drain (as above).

Remember, it should have a rubber seal along the top.

Place it underneath. Again, note that the hole is facing the overflow drain.

While holding it underneath, place the top drain, lined with the foam gasket underneath.

Side note: some people don't trust these gaskets as they can leak. I've never had any problems. But you can use a ring of putty or silicone instead, then go to the next stage and remove the excess.

Screwing the Kitchen Sink Waste Drain

Then place the long screw provided in the centre of the drain.

Above, I'm carefully screwing it tight with a flat head screwdriver.

Note, don't rush this as you don't want to accidentally slip and scratch or dint your sink.

Installing the Overflow Pipe for the Kitchen Sink Waste

Depending on whether your sink is round or square will depend on what rubber seal you use.

Ours is square, so I used the bottom one in the pic above.

Simply press is down on the square section that leads to a pipe.

Here's where it goes. You'll need to hold it in place with one hand to perform the next stage.

While holding the overflow kitchen sink waste pipe, thread the screw through from the sink side to grip it.

Attaching the Overflow Pipe to the Kitchen Sink Waste Drain

Here's how it works.

Place the drain screw over the pipe. I also have a black rubber seal in my hand to insert the opposite drain spout.

Cut Your Overflow Hose Down Unlike this Picture

Something I learn since this picture, was to cut the overflow pipe down prevent from sitting on the bend and stagnating.

Once cut with a hacksaw, thread the plastic drain screw to grip it.

Adding the Sink Trap

Next, you'l need to add your sink waste trap. It's a good idea to work from here, then lead to where your waste pipe after.

You can't see it properly here, (although you can below), but my McAlpine sink trap has an extra spout for a washing machine hose. This could also be used for a dishwasher instead.

First, screw it tight to the sink drain.

Attach your Washing Machine or Dishwasher Hose

There are a handful of ways you could do this. I decided that instead of drilling a hole for another waste pipe, I linked my washing machine hose to the sink.

However, it's vital that you use a jubilee clip and screw it tight with a screwdriver. This ensures it doesn't come off.

Note I connected this much later, hence why I have something underneath to catch water.

Working on the Waste Pipe

I needed to cut a series of waste pipes and elbows first while also ensuring my waste pipe wasn't too steep.

For a full demonstration, you can watch my video from here to follow along.

I also had a drill a hole at the back of the kitchen units to fit it. Note, I had to be careful my combi drill didn't rub and wear away any of my speedfit plumbing.

Once I'd made sure my waste pipe slope using the 1cm in 40cm method. Note, this is important to ensure food waste doesn't get stuck and create smells.

I.e, if it's a gentle slope, the water doesn't run away as quick, so will more likely clean the pipes on the way down.

Then fit the last section of waste pipe.

Note, if this is tight, then try to use washing up liquid for easy fitting.

And finally, I added some pipe clips to prevent the waste pipes from getting knocked and that's it!

I now have a working tap and sink that I can use when cleaning up after food blog cooking sessions at Tastefully Vikkie.

More Fitting a Kitchen Projects

• You can find my complete list of fitting a kitchen projects here
• Changing a mixer tap
• How to replace a leaking sink drain