It could take more than two years and cost millions of dollars to eliminate a strange smell in the tap water at some houses in Halifax, according to the Halifax Water Commission.

People first started complaining about the stinky drinking water late last summer.

Officials with the Halifax Water Commission had hoped cooler temperatures would solve the problem, but residents said they still get whiffs of the marshy smell.

"As recently as last night when I turned on the tap to wash dishes, I got the swamp smell again," said Kathi Vinson from Wedgewood.

Linda Mosher, the councillor for District 9, said she's been getting a call every day about the smell.

The odour is unpleasant, but officials say the water is safe to drink.

A compound called a geosmin, which Halifax Water has never had to deal with it before, causes the smell.

People with sensitive noses can detect just a teaspoon of geosmin dropped into enough water to fill 200 swimming pools. If the water is heated for something like a shower or cooking, the smell is even stronger.

James Campbell, a spokesman for Halifax Water, said the utility is studying treatments.

"One is a powder-activated carbon or a granular-activated carbon system or an ozone system," he said.

If a new treatment is needed it take months to design, install and approve a water rate increase to pay for it.

Until then, Vinson said she and other customers might ask for compensation.

About two-thirds of people who use Halifax Water get it from the Pockwock Lake reservoir.