Tenants with one spare bedroom have had a payment reduction of 14% and those deemed to have two or more spare a reduction of 25%.
Lawyers for the 11 cases say that, unless the families move from their homes into smaller properties, they face building up rent arrears and being forced out any way.
More top news
The presidential candidate has called for the FBI to fully explain the new emails that have come to light.
The American Airlines plane caught fire at Chicago O'Hare airport, prompting an evacuation of the plane.
As the number of people sleeping rough in England increases significantly, a new bill aimed at cutting homeless has passed a second reading.