Intermittent bad smell in house (not like rotten eggs) driving me mad. Any suggestions please?

[SRyan]

Now and then I get a terrible smell in the house. It doesn’t smell like rotten eggs so does that rule out sewer gas or a problem with the stack pipe?
It’s difficult to explain the smell as I haven’t smelled anything like it before. I smell it in the kitchen and living room (which is above the kitchen). Also sometimes there’s a mild unusual smell from one of the toilets.
At first I thought it might be to do with a peace lily I bought but the smell got much stronger and was in other rooms.
The upstairs toilet leaked a few years ago and the contents came through another room (neither the toilet or the room it leaked into smell) but I was wondering if it could be mould?
Most of the time the house doesn’t smell. Could it be to do with humidity or something to do with vents on windy days?
Is there a way of testing to work out what it is?
Thanks

 

[Wayners]

Melted switch smells a bit fishy. The shower puil cord was like that and could not find cause for months. Was well burnt out.

Washing machine waste pipe can smell if you have one.
Dead mice is another
Frog season and found 3 dried up under furniture over the years working in houses.

List goes on

 

[DetlefSchmitz]

Is there a basin, bath, shower or toilet that you rarely use where the water in the trap may have been blown out by the wind?

 

[SRyan]

Melted switch smells a bit fishy. The shower puil cord was like that and could not find cause for months. Was well burnt out.

Washing machine waste pipe can smell if you have one.
Dead mice is another
Frog season and found 3 dried up under furniture over the years working in houses.

List goes on

Would the washing machine waste pipe smell travel through the house?
Our block of terraced houses had a rat problem last year. They didn’t come into our living space but we heard scratching in the wall so called out pest control. They said they travel along the subfloor (other houses heard them too). No sign of them in a long time though

 

[SRyan]

Is there a basin, bath, shower or toilet that you rarely use where the water in the trap may have been blown out by the wind?

Yes there is What would I do about that? Would running the water in it fix it?

 

[ChrisJP]

If a trap has its water blown out, or evaporated, just run the taps for a little while to refill the trap.

 

[SRyan]

If a trap has its water blown out, or evaporated, just run the taps for a little while to refill the trap.

Thank you