Smelly under sink cupboard

[Umpalumps]

Help please! We had a new kitchen fitted around Christmas time. After a few weeks a foul stink has been developing in the cupboard under the kitchen sink. We had all the pipes replaced and the walls skimmed. It’s like a rotten smell. I’ve tried soda crystals down the sink and bleach etc but it absolutely stinks. Any ideas? I’m really worried there might be a leak although there is no sign of one

@Umpalumps Hi - not sure if it’s the same thing but we had this sewage smell after out kitchen extension was done.

Turned out that they had blocked off the old sink drain but hadn’t done a great job. Can’t remember exactly what had happened but maybe double check on your plans where the dishwasher outlet goes to and whether any drains were blocked up. Could waste water be leaking into old drain and not escaping anywhere?

@Verbena17 thank you for your reply. I don’t think its that because we didn’t move anything round in the kitchen- same layout just new cupboards, pipes and sink etc.

Lots of photos please. Do the waste pipes go through the wall to an outside drain? Or connect to a soil pipe in the corner of the room?

Include photos of outside draIns and manholes.

How old is the house?

Is the kitchen in the original place, or an extension?

oh @PigletJohn of all people to respond 😀😀 I can’t get one of the outside at the moment but I have included pics of under the sink. House is late 40’s / 50s. Waste pipes go through the wall to the outside. Kitchen is an old extension (we think around 80’s / 90’s.

I will get one of the outside tomorrow, I know the waste pipe leading out to the outside drain was replaced when our new kitchen was put in

Stand back and take some wider pics please.

I get this problem. Kitchen sink smells foul (rotten eggs) when I flush the downstairs loo.

and only in winter.

such a puzzle