The real property of the state, including the real property held in the name of state agencies and funds, and the real property of a political subdivision of the state are exempt from attachment, execution, and forced sale. A judgment lien or abstract of judgment may not be filed or perfected against the state, a unit of state government, or a political subdivision of the state on property owned by the state, a unit of state government, or a political subdivision of the state; any such judgment lien or abstract of judgment is void and unenforceable.
Tex. Prop. Code § 43.002