Flooding throughout Otago last weekend overwhelmed several water-treatment plants there.
Clutha District Council deputy chief executive Jules Witt said water-treatment plants were running again, but it would take time for a supply of the treated water to build up.
The Kaka Point and Richardson South rural water schemes were both low, he said, so conserve-water notices were in place.
"Those are two that are particularly low, and they've had very low levels in reservoirs for a number of days now, so people may well be getting short of water there."
Households on the Tapanui, Stirling and South Bruce supplies were still under boil-water notices.
"It will be a little bit longer for the boil-water notices [there], because once the water's up to spec, it takes time for it to be flushed through the whole system as well."
Witt said tankers were available for drinking water in communities with short supply.
