Low gas pressure affected 475 homes, a number of care homes and four schools across the Leyland area this morning after the gas was turned off for safety reasons.
The National Grid says a problem in the system caused a safety mechanism to shut off the gas but it has since been investigated and the gas has been restored.
The low pressure meant there was a very small amount of gas in the pipes across the area and appliances may not have worked properly.
St Catherine’s R.C Primary School, Farington, Wellfield High School, Leyland, Northbrook Primary School, Leyland and Balshaws C of E High School were all forced to close due to a lack heating.
The school’s remain closed but are set to re-open tomorrow.
Jeanette Unsworth, The National Grid’s press officer for the North West, said: “The gas has been restored.
“A piece of safety equipment turned off the gas in the area as a precaution after a problem caused it to trigger.
“We do not know what caused it to happen but we have worked to get the network safe and gas pressures back to the normal level.
“Our engineers will be going door-to-door to visit homes that reported pressure problems.
“We have received calls from across the Leyland area.
“A number of homes, care homes and schools have been affected.
“If anyone is still having difficulties with their gas supply or if they smell gas they should call us on: 0800111999.”