As of the censusGR2 of 2000, there were 15,106 people, 6,371 households, and 4,058 families residing in the city. The population density was 698.5/km² (1,808.3/mi²). There were 7,322 housing units at an average density of 338.6/km² (876.5/mi²).
There were 6,371 households out of which 25.3% had children under the age of 18 living with them, 48.0% were married couples living together, 12.3% had a female householder with no husband present, and 36.3% were non-families. 31.0% of all households were made up of individuals and 17.7% had someone living alone who was 65 years of age or older. The average household size was 2.30 and the average family size was 2.86.
In the city the population was spread out with 22.6% under the age of 18, 7.5% from 18 to 24, 23.3% from 25 to 44, 21.0% from 45 to 64, and 25.7% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 84.2 males. For every 100 females age 18 and over, there were 79.7 males.
The median income for a household in the city was $32,032, and the median income for a family was $39,519. Males had a median income of $30,807 versus $22,072 for females. The per capita income for the city was $18,706. About 11.0% of families and 15.3% of the population were below the poverty line, including 25.2% of those under age 18 and 9.6% of those age 65 or over.
Eustis also serves as the center for many small communities of Rural East Lake County including Cassia and Pine Lakes. These communities are not reflected in the Census Bureau's City Statistics but make up for the vast discrepancy in county to city stats. When the rural statistics are compiled into the city stats, the total population of Eustis topped 50,000 in 2000.