A couple who received complaints from their neighbour claiming cigarette smoke was causing a nuisance say tests have now been carried out.
Jeanette Gordon-Crawley says tests have been carried out
Gwynedd council confirmed it was investigating a complaint about a couple smoking in their own home.
Two smoke bombs were let off in Jeanette and Gavin Gordon-Crawley's living room in Caernarfon and they hope to have the results next week.
Inspectors visited the adjoining house to find out if smoke came through.
According to Mrs Gordon-Crawley, 54, who lives in a semi-detached house, the smoke was not visible but it could be smelt.
She described the amount that could be smelt as "minute".
Mrs Gordon-Crawley said she is a social smoker and Mr Gordon-Crawley, 51, smokes around 20 cigarettes a day.
'Hoping to hear'
It is thought the odour could be permeating through a ventilation tile or grid in the wall of the house next door.
"My husband made a comment that you'd need a thousand people in the room to smoke that much," said Mrs Gordon-Crawley.
She invited the environmental health inspectors to carry out the test after being notified of her neighbour's complaint.
"I'm just waiting for them (the council) to make some recommendation. I'm hoping to hear by the end of next week."
She said she has not seen or spoken to her neighbour since she made the complaint.
A spokesman for Gwynedd council said: "Whilst the council does not discuss individual cases, we can confirm officers are investigating the matter and are in communication with the residents".