When Sydney couple Sarah McGilvray and James Couche opened their doors to potential buyers at the weekend, they expected the open house to be fairly uneventful.

But returning home after the inspection, they immediately noticed something wasn't quite right.

McGilvray, a breakfast radio presenter, and her husband had put their three-bedroom terrace in Sydney's inner west suburb of Balmain on the market after buying it last year for AU$2,040,000 ($2,208,000).

The pair have since renovated the property, and hope to pocket about $2.1 million when it goes under the hammer on June 28.

Start your property search

Find your dream home today.
Search

But McGilvray has revealed that the open home did not go smoothly.

She told radio listeners that she noticed a "smell that wasn't right" as soon as she returned home after the open home.

"I was sitting with Mum in the living room and I just couldn't get my head around a smell that wasn't right," she said.

"I thought, 'Are those flowers off? No, they're brand new — what is that?' There was something a bit weird.

"I went to the bathroom and there's footprints on the floor. But they didn't just walk into the bathroom.

"They've taken their liberties with it … and used the facilities, shall we say."

McGilvray, who said she had spent "hours scrubbing" and "sprucing the joint" before the open home, said the mystery toilet user had tried — and failed — to keep things clean.

"To their credit they did pull the chain … but left a mess," she said.

She said the agent had confirmed "quite a few people" had visited the house during the inspection, and that the bathroom user had put the couple in an awkward and embarrassing situation.

"Anyone who came through afterwards would have thought it was us and that we don't know how to clean up after ourselves," she said.

The three-bedroom, one-bathroom home on a 135sq m block, boasts harbour views.