Greenwater, WA has a population of 100 and is the 26,935th largest city in the United States. The population density is 69 per sq mi which is 29% lower than the Washington average and 24% lower than the national average. The median age in Greenwater is 49 which is approximately 31% higher than the Washington average of 38. In Greenwater, 41% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 74% of Greenwater residents were born in Washington, 26% were born out of state, 0% were born outside of the United States and 0% were foreign born.