The Huurcommissie has books/guidelines on what a constitutes a defect. Every year this book is updated and the changes are outlined. The books are always published only in Dutch. This translated copy should make it more accessible to the non-dutch renters who want to know more about what classification their defects are. Class A defects can get up to an 80% temp reduction on the rent price Class B defects can get up to an 70% temp reduction on the rent price Class C defects can get up to an 60% temp reduction on the rent price