The size of Wanniassa is approximately 5.4 square kilometres. It has 35 parks covering nearly 12.5% of total area. The population of Wanniassa in 2011 was 7,786 people. By 2016 the population was 7,525 showing a population decline of 3.4% in the area during that time. The predominant age group in Wanniassa is 60-69 years. Households in Wanniassa are primarily couples with children and are likely to be repaying $1800 - $2399 per month on mortgage repayments. In general, people in Wanniassa work in a professional occupation. In 2011, 74.4% of the homes in Wanniassa were owner-occupied compared with 76.2% in 2016. Currently the median sales price of houses in the area is $850,000.