With a year-round population of about 1000, Block Island's population in the summer swells to over 10,000 persons.  The Island's water resources consist of a designated sole source aquifer, coastal embayments, drinking water reservoirs, freshwater wetlands and ponds which are all vulnerable to contamination.  The Island is a popular eco-tourism destination and the strength of the local economy depends on the health of the water resources and the unique natural areas.  Appropriate on-site wastewater treatment is essential to prevent pathogens and nutrients from harming the potable water supply and maintain recreational and commercial fish, shell fishing, boating, and swimming.