During a survey of the school carried out by Dumfries and Galloway Council, raised levels of the heavy metal were found in single water sample, prompting further investigations.
And pupils will now be transported to the partnership school at Carruthertown while investigation work is carried out.
A spokesman for the local authority yesterday said: “This water sample was taken after a weekend, when water had been standing in pipes for two days.
“Further water samples have subsequently been taken and, although these have indicated reduced levels of lead from the first sample, they are still at a higher level than would be expected.”
Young children who are exposed to lead can suffer a number of worrying symptoms, including abdominal pain, vomiting and hearing loss.
The school kitchen is supplied with water from another source and is not affected by the raised lead levels.
He continued: “The wellbeing of pupils and staff is always our primary concern and, since we were informed of the result of the initial sample test, we’ve provided the school with bottled water.
“We are currently working with Scottish Water to investigate the source of lead. The school does not have any lead pipework or a lead water tank.
“Further investigations will require heavy plant and excavations which could take around three weeks, so it has been decided to decant pupils and staff to the partnership school at Carrutherstown from Monday February 25.”
He said arrangements are in place to transport pupils to and from Carrutherstown each day and lunches will be provided.
A public health spokesman said: “Within half an hour of receiving the results of the water test, we held an incident management meeting.
“The next morning bottled water was supplied to the school.
“Parents were notified of developments and given the opportunity to speak to the public health team.
“We are taking national advice and a Q and A sessions is being organised for parents and guardians.”
