Key Points:

Continuing hot, dry weather has prompted Dunedin City Council (DCC) to impose water restrictions from today.

The restrictions, across the city, prohibit the use of garden sprinklers at all times and allow hose irrigation and car washing only between 8pm and 8am.(crrct)

But the car-washing ban doesn't apply to residents with water meters.

DCC water production manager Gerard McCombie said flows in the Deep Stream catchment had fallen to the point where the flow in its pipeline was being reduced to maintain residual flows in the stream.

In the Waikouaiti River catchment, the flow had fallen to "very close" to the residual flow consent limit.

"In Mosgiel, the daily demand in recent times has reached 87 per cent of the consent limit and so restraint is required there also," Mr McCombie said.

Demand in metropolitan Dunedin meant there was only a modest surplus of supply over demand on some days, he said.

Unless demand could be controlled, water would have to be pumped from the Taieri River to keep city reservoirs topped up.

The weather forecast was for a continued dry spell until the end of March.

Mr McCombie said restrictions would apply across all the city's water distribution areas and remain until there was significant rain in the catchments.

If the supply situation worsened, restrictions may be increased , he said.