Residents in Townsville have been told to stop all water use other than drinking and flushing toilets as water supply hits a critically low level.

Townsville City Council told all residents to restrict water use in the northeastern Queensland in the coastal city on Saturday morning.

Residents were first told to start conserving water after a 1.3 diameter pipe ruptured at the Douglas Water Treatment Plant on Friday at 2pm.

The leaking pipe is the main tube that feeds into the treatment plant, giving Townsville its fresh and clean water.

By 8pm Friday residents were told they could only use water to flush the toilet or as drinking water, the Townsville Bulletin reports. 

Staff from council have been onsite assessing the extent of the damage ever since it started leaking on Friday. 

Investigators immediately isolated the pipe to inspect it and began repairs.

From Saturday morning, residents were told to turn off their irrigation and not to do any handheld watering.

They are not allowed to shower, wash any clothes or dishes, fill up pools or wash vehicles and boats.

Council staff have been joined by contractors BMD, NQ Excavations and CivilPls who have been working overnight to replace the ruptured pipe.