'Smelly water' causes school closures
Schools have been closed and thousands of people told not to cook, drink or wash with tap water after concern over its taste and smell.
The alert affects about 6,000 properties in the Carfin, Newarthill, Chapelhall, New Stevenston and Dalziel Park areas of North Lanarkshire.
Scottish Water said it had been told the water had an "oily based substance" with a strong odour.
North Lanarkshire Council said nine schools would remain closed on Friday.
It has advised people to only use mains water to flush their toilets.
The two secondary and seven primary schools are: Taylor High; St Theresa Primary School; Brannock High; Keir Hardie Memorial Primary School; Our Lady and St Francis Primary School; New Stevenston Primary School; St Patricks Primary School; Chapelhall Primary School and St Aloysius Primary School.
A spokesman for North Lanarkshire Council said: "While Scottish Water is working hard to resolve the issue, we have taken the decision tonight that schools in the affected areas will remain closed on Friday.
"This is a precaution and to allow parents time to make childcare arrangements if necessary."
Bottled water has been delivered to between 3,000 and 4,000 properties by about 100 Scottish Water staff, who have warned residents not to use tap water even if it had been boiled.
Efforts are continuing to deliver bottled waters to affected properties which have not yet received any.
Further water supplies have also been made available for collection at Kirkhall Road in Motherwell and the Lidl store in the town's Carfin Street.
Scottish Water's chief operating officer Peter Farrer said: "Initial investigations suggest an oily substance is in the network. We are continuing to carry out sampling and investigations on the network as part of these ongoing investigations - and these will continue as a matter of priority to confirm the cause and resolve the issue.
"We will issue further updates when more information becomes available, and we will closely monitor the network and advise when the water is back to normal."
Extra support has been given to elderly or disabled people, care homes and hospitals.
Anyone wanting more information can check Scottish Water's website or call its customer support number on 0800 0778 778.