Rainwater Harvesting and Treatment: Objectives, design description, and criteria Water goals at the NNH began with questions surrounding the appropriate balance between public and private services as they relate to safe, convenient, efficient and environmentally responsible water use. The project team worked to find a solution that satisfied the stipulations of the temporary permits and would function without onerous maintenance by the residents. The team also obtained variances for use of treated rainwater solely for toilet flushing, clothes washing and exterior hose faucets.