The tax is not levied upon the value of the original basis price of the home, nor is it levied against the current tax-free gains that most home sellers of personal residences qualify for: $250,000 of tax-free gain for single tax filers, and $500,000 for a married couple filing jointly on personal residences.
At this point, all income earners under $200k/$250k are exempt, and all transactions without a gain of more than $250k/$500k are exempt. This makes up the majority of real estate transactions today.
Understanding The New 3.8% Health Care Tax on Real Estate | Seattle Waterfront Homes – seattlepi.com