Fairfax County supervisors this week questioned why two nonprofit groups needed to restructure their loans for affordable housing projects, raising concerns that the county had become a financial fallback for nonprofits in trouble.

Proposals from both the Wesley Coppermine Limited Partnership, which runs a 66-residence development for the elderly in Herndon, and Chesterbrook Residences Inc., which runs a 97-unit assisted-living facility in McLean, came before the board on Monday. Chesterbrook was seeking an additional $275,000 loan from the county after seeing shortfalls due to an unexpected stream-restoration project. Wesley sought to restructure the terms of its $794,000 county loan after ongoing construction caused overly high vacancy rates at the development.