Water restrictions have come into effect today in Christchurch. 

The City Council has imposed level three restrictions to keep water use down while critical work is done on well heads.

It will help the council meet its May deadline to remove chlorine from water supplies.

Water Supply Improvement Programme Manager Helen Beaumont says it means hand-held hoses and watering cans only.

"No sprinklers and no irrigation systems. And it's on alternate days, so if you live at Number 1 or 3 in your street, then you can water on odd numbered days. If you live at 2 or 4, you can water on even number days." 

Beaumont says most people comply and will let their neighbours know about the restrictions.

"And if that doesn't work and we are seeing some very high users, usually the first approach is education, we go and talk to people. And usually that works." 

She says the restrictions don't apply to the Botanic Gardens, which has its own bore.