Smelly drains - please help

[MsTea]

We've just moved into a new house. One of the first jobs we did was unblock the bathroom sink drain, which was draining really slowly, but it's left it smelling dreadful! We've tried bleach, disinfectant, more drain unblocker stuff, flushing it with boiling water, bicarbonate of soda and vinegar and nothing has worked. I'm getting desperate - I'm 12 weeks pregnant and not feeling particularly gastrically robust at the best of times, so brushing my teeth and washing my face has become a bit of an ordeal. Does anyone have any more ideas or do we have to call the professionals in?

Oh no how awful for you.
To be honest I'd only suggest what you've already done, sorry not helpful. My DH has put washing powder down then boiling water and plunger but I don't think it's been as bad as you're experiencing.
Hopefully someone with more knowledge comes along.

Have you removed the U bend to see if anything is stuck there?

You need to get to the source of the stench and remove it.

If I was feeling sick I'd get someone else to do it. We had to do this in the U bend in the kitchen.
It was so gross that I got new parts from a DIY shop rather than to try to clean what I saw. It was pretty cheap too. No more smells....joy!

Most often it is a grease-related blockage. Hot water and Washing Soda Crystals will reduce it. In future spoon crystals into the plughole and the overflow once a week and add just enough hot water to wet them, not to wash them away.

But for now take off the sink trap, scrape it out, and put it in a bucket of hot water and soda for an hour. Put a spare bucket in the cupboard under the sink because somebody is sure to run water unto the sink or tip the bucket down it, even if you tape a big sign across it.

Please post a photo of the waste pipes and trap, including the hose for dishwasher and/or washing machine if they connect to the sink drain.

Is there a yard gulley outside the kitchen?

How old is the house?

House is only 12 years old (ish). It's our en suite, not kitchen and I don't know how easy it is to remove pipes - it's a bit cramped in here. I'll try to post pictures though, if I can work out how to on my phone.

Will try the soda crystals in the meantime. Thank you!

This is what it looks like behind the offending sink.

I think those might be the water supply pipes. I can't see a trap or a waste pipe. Put your hand in the pic to show scale please.

Under the basin plughole will (should) be a trap shaped something like P or bottle usually white plastic, might be chrome.

The waste pipe will probably join up with a soil pipe of 110mm diameter. If you can see the top of the soil pipe please take a photo. It might have a plastic cap on it.

First rule of drains, they must slope downhill.

BTW I see the basin has a pop-up waste. This will leak. Change it to one with a plug when you have time.

Is this the waste pipe? Sorry for the dreadful photo, it's tucked right into the sink stand and I just had to turn my phone and hope for the best! The pop up thing does leak (I'm very impressed you can tell that from that pic!), we will change that when we get round to it.

Not sure, it might have a sort of bent-round tube like a trumpet inside that casing. Undo the big white nut top and bottom (rubber gloves will help you grip them) and pull it out, see if it has a trap and if it is clogged with grime.

Or could it be one of these? The trap should be attached to the threaded pipe that comes straight down from the plughole.

I do however suspect that the smell is coming into the basin from the soil pipe which might not be properly vented, so start asking local friends and neighbours for a recommended local plumber. This is especially likely if the en-suite was added after the house had been built.

this is what I meant by "bent round like a trumpet" but I think yours isn't.

I will bow to pigletjohns knowledge, but when I moved in to my new house one the pop up plugs was leaking, poor draining and smelly I unscrewed it remove a mass of hair etc. And screwed in back in. No leaking, free draining and no smell.

good point, if it turns out to be hair in the waste and trap, cleaning it out will be a good start.

I have hear that squirting Nair cream down the plughole dissolves it, but have never tried that.

It looks more like the first one you linked to. I'll try to remove that and give it a good clean / soak in the soda crystals tonight and see if that helps.

The en suite was built when the house was. We have a good plumber from the last house (we haven't moved far) so I'll give him a ring if this doesn't work.

Lonecat - the plug thing has already been thoroughly cleaned and given a tentative sniff and that isn't the problem unfortunately. It would be so easy if it was! Thanks for the suggestion though.

And a big thank you PigletJohn, your advice has been much appreciated.