The smell should go away as the reservoir cools. (CBC)

An unusual organic matter is creating a strange smell in some Halifax tap water, but officials say it is safe to drink.

Halifax Water says about 24 customers have called to complain about the odour.

"In some areas of Halifax served by the Pockwock water supply, we've experienced some calls from customers related to a smell, a kind of earthy, musty smell. We believe it's related to a naturally occurring organic matter called geosmin," said spokesman James Campbell.

"There's absolutely no concern health-wise. It can produce an unpleasant odour and taste, but as far as health concerns, the water is perfectly safe to drink."

The Pockwock Lake reservoir is the main one serving the Halifax side of the city; about two-thirds of people who use Halifax Water get it from Pockwock.

Campbell said the summer weather was behind the smell.

"Geosmin is a naturally occurring material that's in fresh-water lakes. The reason we're experiencing it around here for the first time is that we had a hot dry summer, then a heavy rain in September, which are the perfect conditions for geosmin to occur," he said Monday.

Tips for getting rid of smell

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

Campbell said there are ways to deal with the stinky water.

"They can put it in the fridge in an open container and let it breath overnight, they can squirt a little bit of lemon in the water [or] they can put it in the blender and blend it for five minutes," he said.

Halifax Water hopes the smell will go away on its own as the lake cools, but if it persists they will look at treatments used in areas where geosmin is common.