Up to four inches of drain water has leaked into the gardens of two properties
A drain leak which has created what has been described as a "river of sewage" is being investigated by Severn Trent Water.
Elsie Beaumont, who owns one of the affected properties on Blackberry Lane in Coventry, said: "The smell is absolutely awful."
She said the water company had been contacted on Thursday once it became clear the fault could not be cleared by a plumber.
Severn Trent said it had an engineer on site, looking into the cause of the problem.
Mrs Beaumont's tenant, Roger, told BBC Coventry and Warwickshire he was alerted by a neighbour.
"When I walked out there there was this awful smell and I could see the sewage in my garden," he said.
He said he was worried about the surrounding area being contaminated.
Mrs Beaumont said she stopped a man from walking through the water.
She added: "I don't know what it's going to take to get rid of the mess, how far down we're going to have to go to try and clear some of it."