Some potential health hazards include infectious hepatitis, diarrhea, and cholera. A single discharge in a low flushing environment such as a marina can be detected for at least one square mile. Sewage acts as a fertilizer in the marine environment, leading to uncontrolled alga growth and subsequent depletion of dissolved oxygen. Low levels of dissolved oxygen can lead to the death of fish and valuable marine plant life. Shellfish beds, swimming areas and fishing areas may be closed because of sewage contamination.
Gray water is the water that is produced during bathing and in the galley.
It is illegal to discharge untreated sewage within three nautical miles of Virginia's coast. Many boating facilities also prohibit the discharge of treated sewage at their facilities. The CVA allocates portions of the grant money for education programs in the states receiving funds. In Virginia the CVA funds are managed by the Virginia Department of Health through it's Marina Program.