With the number of sustainable buildings growing in the marketplace, leasing practices have followed suit. Issues of non-compliance may arise, especially when tenants wish to make alterations to their areas of the property. If an owner has committed to a LEED-certified building and a tenant threatens that certification, the owner should seek traditional remedies -- repair at the tenant's cost or termination of the lease. Currently, there are very few areas where an owner would be required to implement green practices in their buildings, but that trend may be changing. More and more projects are going green, and owners, managers and tenants need to consider how the change affects their legal relationship and obligations to one another.