The raw effluent, which includes 'human waste', has overflowed from the drain and has affected the water systems of nearby properties along Market Place in Great Bridge.
Engineers have now cleaned up the mess which has been overflowing since last Monday.
Mother-of-one Louise Birch, who shares the garden with an opticians below her first-floor-flat, said waste water was getting into her sink and shower.
Miss Birch, aged 39, who lives with her six-year-old daughter Charlotte Willetts, said: "The problem has happened about five times in the last 12 months.
"Severn Trent Water comes out and clears up the mess but then they don't fix the problem permanently.
"I have been unable to use my toilet, shower or washing machine. When I turn on the washer, waste water comes up the sink. If I flush the toilet, water comes up and out the shower.
"We can't wash in dirty water. The sewage contains human waste. We are getting desperate now, we can't keep living like this."
Miss Birch said she has had to take her daughter to her mother's house in West Bromwich to be able to wash.
"It is not ideal travelling at 6pm each night to get there," she said. "I have been feeling ill since the sewage started appearing."
Sarabjit Mann, who owns The Great Bridge Eye Care Centre beneath Miss Birch's flat, said she has lost custom because of the sewage. Her businesses also shares the garden.
She said: "I had to close my facilities on Tuesday. I haven't been able to use my toilet or sink for the past week.
"Having had no income has obviously affected me. The shop absolutely stinks of sewage. I can't expect patients to feel welcome in the shop."
Miss Birch complained that Severn Trent Water had been slow in dealing with the problem.
"They came out on Sunday morning and cleared it, but it has not solved the issue," she said. "We were told it was caused by fat blocking the drains.
"I first noticed the sewage last Monday. I phoned Severn Trent last Tuesday and they sent out two crews, who told me they couldn't clear it.
"A site manager attended on Friday and said a crew would be out within two hours, but no one came until Sunday."
Severn Trent said engineers from their partner Amey attended to clear up the mess. Engineers had cleared up the majority of the sewage.
A spokesman for Severn Trent said: "We've been called out to an address in Market Place, Great Bridge, on two occasions over the past two years – first in October 2015 and for a second time last week – after sewage overflowed from a manhole cover.
"In each case engineers from our partner Amey have attended to clear up the mess and to unblock the pipe that was causing the issue.
"We believe that the blockages are down to fat, oil and grease being poured down drains – these liquids are then solidifying in the sewer and causing the problem.
"We're really sorry for the issues that have been caused, especially to those residents who live near to the affected manhole.
"We'd remind everyone to help protect our sewers by putting oil and fat in the bin or use one of our special 'gunk pots' which are available to order for free by visiting stwater.co.uk/gunkpot"