New Rules to CMHC Mortgage (Canada Mortgage and Housing Corp) Real Estate Topics Cowichan Valley CMHC tightens mortgage insurance rules starting July 1st, 2020. The government-backed Canada Mortgage and Housing Corp said on Thursday it would tighten rules for offering mortgage insurance from July 1, after forecasting declines of between 9 and 18 per cent in home prices over the next 12 months. Have questions on how this could impact your buying or selling goals... Call me.