Capital gains tax

[Lisa R.]

Hello All-I need help! Is there really no capital gains tax on the sale of real estate in Washington state?? What’s the catch? That sounds too good to be true. What am I missing? 
Also- can anyone answer a question regarding the $250,000 exemption from gains when you sell a property in Washington state as a single filer? Does this exemption amount get subtracted from the sale price of the property, or the assessed value of the property? 
or can somebody possibly just point me to the direction of where I can find the information I need?? 🙏🙏🙏

Thank you so very much!!!