Photo: 123RF
Picton and Waikawa residents are being asked to limit their sprinkler usage to conserve water.
Marlborough District Council said the hot weather, high demand and reduced water levels in the Essons Valley dam are pushing the supply to its limit.
People are being asked to limit sprinkler use to alternate days, and consider how they can conserve water by installing flow limiters on taps, not leaving automatic irrigation systems running for long periods and to irrigate at night wherever possible.
Properties with an even numbered street address may use sprinklers only on even numbered calendar days, while odd numbered addresses may use sprinklers only on odd numbered calendar days.
Only one tap may be used at a time to run a sprinkler or sprinkler systems.
Handheld hoses can still be used but the council said this should be limited.
If the measures do not reduce demand, level two restrictions will be introduced - banning sprinkler use and only allowing watering by handheld hoses.
Water levels at Picton's other supply in Speeds Road are healthy and the treatment plant is operating at full capacity.
All other water supplies in Marlborough - Blenheim, Havelock, Seddon, rural Awatere, Wairau Valley and Riverlands - are currently unaffected by the dry weather.
According to MetService meteorologist John Law, much of the country will experience an "incredibly warm" and muggy feel overnight into Wednesday.
Temperatures across the country would be in the mid-to-high 20s - and some hot spots reaching above 30 degrees, MetService said.