Residents are asked to bring their water to a rolling boil for one minute before consuming it, brushing their teeth or washing vegetables that won't be cooked. (CBC)

A boil water advisory has been issued for all Saint John residents east of the Reversing Falls Bridge, with the exception of those in the Millidgeville area.

There was a failure in the chlorination system at the Latimer Lake Water Treatment Facility on Friday morning, say city officials.

"The presence of low chlorine means that disinfection may not be effective and thus there may be bacteria in the water that can cause illness in humans," a statement says.

"These organisms can cause diarrhoea, cramps, nausea, headaches, or other symptoms." Infants, young children, the elderly and people with compromised immune systems are at increased risk.

City officials have increased chlorination levels at the treatment plants and are working with the Department of Health to test the safety of the water.

Meanwhile, all residents are being asked to use bottled water or to bring their water to a rolling boil for at least a minute before drinking it, brushing their teeth, making ice, juice, coffee, tea, or washing vegetables that won't be cooked.

Boiling kills bacteria and other organisms in the water.

It is safe to bathe with the water. It is also safe to wash dishes in the dishwasher, or by hand with hot, soapy water and then air dry.

May be extended to Millidgeville

Water users in the Millidgeville area not affected by the boil order are being asked to conserve water until the order is lifted.

"Depending on the effectiveness of the water restrictions and the duration of time it takes to resolve the situation at the Latimer Lake Water Treatment Facility, the boil water order may be expanded to include the Millidgeville area," the statement says.

The areas of Millidgeville not currently affected by the boil order include those north of:

• The intersection of Spar Cove Road and Belleview Avenue.
• The intersection of Millidge Avenue and Ropewalk Road.
• The Atlantic Superstore on Somerset Street.

This is the second boil water order in as many months in the city.

An order was issued on Feb. 9 for anyone living west of Rothesay Avenue and Russell Street after a water main break on the city's east side.

The order, which affected about 35,000 people, was lifted on Feb. 12 for most customers, other than a commercial stretch of Rothesay Avenue.