As of the census of 2000, there were 10,467 people residing in Port Washington. The racial makeup of the city was 97.0% White, 0.7% Black or African American, 0.5% Asian, 0.4% Native American, 0% Pacific Islander, 0.6% from other races, and 0.89% from two or more races. 1.5% of the population were Hispanic or Latino of any race.
There were 3,244 families and 4,763 households, of which 34.0% had children under the age of 18 living with them, 57.5% were married couples living together, 7.4% had a female householder with no husband present and 31.9% were non-families. The householder lives alone in 26.3% of all households and 10.5% of householders were aged 65 or older. The average household size was 2.49 and the average family size was 3.05.
In the city the population was spread out with 6.6% under the age of 5, 74.2% aged 18 and over, and 13.2% 65 years and over. The median age was 36.7 years. The population is 50.4% female and 49.6% male.
In 1999 the median income for a household in the city was $54,402, and the median income for a family was $62,557. The per capita income for the city was $24,770. About 2.6% of families and 4.0% of the population were below the poverty line.
Interstate 43 passes around Port Washington to the city's west and north. WI-32 passes north to south through the city while WI-33 travels from the west before it terminates downtown.
The Ozaukee Interurban Trail, a bike trail which follows the erstwhile interurban rail line, passes through Port Washington as it traverses Ozaukee County.
The TransPORT taxi service is available within the city and surrounding 2 mile radius.