After riding a post-COVID wave of booming prices, real estate agents say South Australia's housing market is starting to level out.Federal budget tax changes and rising interest rates have house-hunters feeling more hesitant, with expectations price growth could slow as a result.Adelaide real estate agent Tom Hector said interest rate rises in February and March, and especially the most recent one earlier this month, had resulted in much fewer people attending open inspections."A lot of people are taking a lot more caution when buying a property," he said."So with interest rates significantly going up in the last four weeks and more forecast in the next three to four months, there is no question that there is uncertainty in the marketplace right now."On top of the interest rate increases, the federal government announced in its budget last week that there would no longer be a capital gains tax discount on investment properties from next July, while negative gearing will only apply to new housing.House prices in Adelaide have been rising steadily for six years. (ABC News)Mr Hector said these changes were already having a "huge" negative impact on a market that had been hot for six years."Buyers are really working out what their long-term strategy in investing in the property market looks like," he said."Obviously, there has been that grandfather period, but the next 12 to 18 months will be very interesting with house prices, I feel, only rising at inflation figures — that 3 to 5 per cent — whereas we've seen pretty much a 70 to 80 per cent increase in house prices since COVID began back in June 2020."Hope for owner-occupiers?The latest data shows home prices increased 12 per cent in Adelaide over the past year and 1.1 per cent between March and April, even as prices fell slightly in Sydney and Melbourne.Auction clearance rates have fallen from as high as 80 per cent at the start of the year to below 60 per cent.Pranav Patidar was the only bidder at an auction that was held over in Adelaide's east on Saturday.Pranav Patidar wants a more level playing field with investors. (ABC News: Stephanie Richards)Mr Patidar said the interest rate rises and tax changes were likely to put prospective owner-occupiers such as him in a better position over investors, even though he was not successful at the auction on Saturday."Looking at the recent changes and the new dynamics — rising interest rates — I think that's a good opportunity for the people actually looking for a house for themself and maybe less motivation for the investors who where in the driving seat earlier," he said."I think that's a good way of doing things, because it's important that the people actually living in the property have a chance."Sam Doman says investors will be focused on the long-term. (ABC News: Daniel Taylor)Questions about supplyReal estate agent Sam Doman said buyers were hoping the tax changes would lead to lower prices, but they could also result in fewer houses coming onto the market."I believe that people will be holding onto properties a lot longer," he said."We're talking about trying to give properties up for people to get into the market. Unfortunately, I think with these new changes people will hold onto their properties for a lot, lot longer."Karishma Patel and Purvag Nanavati were happy to buy in an area they have lived in for 14 years. (ABC News: Daniel Taylor)Purvag Nanavati and Karishma Patel were the only bidders on a house at Valley View sold by Mr Doman on Saturday.They plan to live in the house for now and then rent it out later.Mr Nanavati said the changes in the budget were "harsh" but it was reasonable to pay tax on any profits they made from selling the home.He estimated the price was $30,000 down from what it would have been earlier in the month, but that would be offset by the tax increase."I know we will be paying more tax when we sell, but it's a long-term investment, so I'm not that worried," Mr Nanavati said.