In 2005 a global effort was initiated to conduct studies for a baseline recommendation for the various components of the International Linear Collider (ILC). Work for the damping rings was subdivided in a number of tasks. This Report contains the contribution to this effort by the Authors as Coordinators of the Task Force on space charge. (A slightly reduced version of this document can also be found as part of the 'Configuration Studies and Recommendations for the ILC Damping Rings', Edts. A. Wolski, et al., LBNL-59449.) The studies documented in thisReport were carried out for several of the reference lattices considered for the baseline recommendation. Space charge effectswere found to be quite noticeable in the lattices with the longest circumference. Although it does not appear that they could prevent operation of any machine having such lattices they do favor achoice of a ring design with shorter (~;6km) circumference at 5 GeV.