The Coatbridge school campus at the centre of health fears is to be tested for contamination.
The independent review team investigating health and safety concerns has confirmed the move.
Water, soil and the integrity of the methane membrane will all be assessed at the former landfill site in North Lanarkshire.
Results will be published ahead of the re-opening of the schools after the summer break on 12 August.
Buchanan High school, St Ambrose High and Townhead Community Centre make up the Townhead Road campus.
Parents, teachers' unions and local residents have been calling for independent tests on the site since fears escalated at a public meeting in June.
More than 16,000 people signed a petition calling for an investigation and for staff and pupils to be tested for toxins.
North Lanarkshire Council said no serious illness had been linked to the schools or the site.
On Thursday, the Scottish government confirmed the recommendation of the review team, saying that Scottish Water would carry out the water tests.
Wider contamination investigation of the ground and in particular the methane membrane installed as a safety measure during construction of the campus, would be arranged by the review team in conjunction with SEPA and other environmental health bodies.
Teachers at Buchanan High and St Ambrose High walked out in the days leading up to the end of term over the health and safety of staff and pupils.
The NASUWT union called for the entire campus to be tested and its two schools to be closed early for the summer.
'True and comprehensive picture'
Chris Keates, the union's general secretary, welcomed the development.
She said: "This announcement by the Scottish government is the result of the courageous and determined stance taken by our members to take strike action.
"The NASUWT has consistently called for a full site survey as the only way to get a true and comprehensive picture of the site and to identify whether there are any potential hazards which could affect the health and safety of staff and pupils."
"The NASUWT looks forward to receiving the results of these tests as swiftly as possible and will consider the findings in consultation with members."
Lynsey McFarlane, one of the parent campaigners said: "This is what we have been pushing for."
"The review team have obviously found enough evidence in just a week-and-a-half to support the fact the site needs tested.
"We are really happy this is being done and trust that the review team will do the job properly."
The three buildings opened in 2012 on a site that was used as landfill for industrial waste, including lead and arsenic, between 1945 and 1972.
In March 2018, bottled water was used at the high schools after blue-tinted water was discovered coming from pipes, with tests later revealing higher than recommended levels of copper. This was blamed on corrosion, and the pipes have since been replaced.
Fears over the safety of the site came to a head after it emerged four former or current members of staff at Buchanan High had received treatment for cancer.
However, the council and health board said specialist doctors did not believe cancer - or any other serious illness - was caused by the schools or the site on which they were built.
The independent review team has met with officials at North Lanarkshire Council and NHS Lanarkshire as well as parents, pupils, staff and unions. It is expected to report to the deputy first minister ahead of the new school term.
The Scottish government said any parent concerned about the health of their child should continue to use local health services.
It said decisions on medical testing would be based on a clinical assessment of the symptoms and signs of an individual and that there is no prohibition of testing of patients where it is deemed clinically necessary.