In this article, our Lincoln Park landlord-tenant lawyers explain what happens if you are being overcharged by a landlord for maintenance and what you can do to correct it. In many commercial leases, tenants are required to pay a share of taxes, utilities, and common area maintenance charges ("CAM"). The tenant's share will typically be proportional to the amount of space leased by the tenant relative to the total rentable space of the building. This "additional rent" will fluctuate from year to year. It is not uncommon for landlords to overcharge tenants for CAM. If the tenant believes this is occurring, their best option is to audit the Landlord's expenses to ensure that all of the CAM paid by tenants is going toward actual expenses and that those expenses are for vendors at market value, rather than inflated prices.