The Inverness Foundation and the Marin County Free Library have agreed to a new five-year lease for the Gables, the building that has housed the library’s Inverness branch since 1986. The foundation will earn $1,400 a month in rent, with an annual three-percent increase—less than its received in the past two years. From 2002 to 2007, a lease agreement provided the foundation just $650 a month; when that lease expired, the county began to pay month to month, as it could not sign a new lease until the foundation brought the building into compliance with the Americans with Disabilities Act. The county funded interior renovations, but the foundation paid $113,000 for outside fixes and the kitchen and bathroom, all of which were completed in 2013, according to Nick Whitney, the president of the Inverness Association, the foundation’s operational arm. Since then, while the foundation and the county have negotiated a new lease, the county has paid $1,829 a month. The new agreement, approved on Tuesday by the Board of Supervisors, reimburses the foundation for the $113,000 but cuts the rent down to $1,400. “We’re hoping it’s enough,” said Mr. Whitney, who said that even the higher rent wasn’t fully covering the maintenance of the 130-year-old building, which has included fixing heating and septic pumps in recent years. The Inverness Association is holding a membership drive at Saltwater Oyster Depot on April 21, to try to lure more members.