Updated August 3, 2026. Quick answer: Idaho requires no witnesses and no notary. It rewrote this law in 2023, replaced the old living-will vocabulary with an advance care planning document, and reduced validity to three things: your identifying details, your signature, and the date. Witnesses and notarisation are expressly optional.
The 2023 rewrite — the vocabulary changed too
Idaho Code section 39-4510 was added by 2023 chapter 307. If you are looking for an Idaho “living will” or “durable power of attorney for health care” you are looking for terms this chapter no longer uses. The instrument is an advance care planning document (ACPD), and it can hold both the instructions and the agent nomination in one document.
What makes it valid — only three things
Any competent person aged eighteen (18) years or older may execute an advance care planning document (ACPD)… Any provisions of an ACPD that are left blank by a person executing the document shall be deemed intentional and shall not invalidate the document. The department of health and welfare may create and promulgate an optional form for the ACPD. Such form is not mandatory. To be considered a valid ACPD, a document must include: (a) The person’s name, date of birth, telephone number, and mailing address; (b) The signature of the person for whom the ACPD is created or the authorized agent of such person; and (c) The date on which the document was signed.
— Idaho Code §39-4510(1)
That is the whole validity test:
- Name, date of birth, telephone number and mailing address.
- The signature of the person, or of their authorised agent.
- The date it was signed.
Two further provisions do real work. Blanks are deemed intentional and do not invalidate the document — so an ACPD with sections left empty still stands, which is the opposite of the usual anxiety about incomplete forms. And the health and welfare department’s form is expressly not mandatory.
Witnesses and notarisation are listed as optional — in the statute itself
An ACPD may but is not required to include the following: (a) The electronic mail address of the person executing the ACPD; (b) Nomination of one (1) or more persons to act as a health care agent… (d) Resuscitation instructions; (e) Instructions regarding pregnancy… (h) Instructions for end-of-life care; (i) A description of treatment objectives; (j) The names and contact information of witnesses to the execution of the ACPD; and (k) Notarization.
— Idaho Code §39-4510(2)
Look at where they appear: (j) witnesses and (k) notarisation sit in the list of things an ACPD may but is not required to include, alongside resuscitation instructions and an email address.
This is not an inference from silence. The statute enumerates witnesses and notarisation as optional elements. Idaho is the most permissive execution standard of any state we have published, and it is the only one where neither witnesses nor a notary is required.
Why you might still want witnesses
Because validity and acceptance are different problems. A hospital in another state, or a provider unfamiliar with the 2023 rewrite, may balk at an unwitnessed document even though Idaho law is satisfied. Adding two witnesses costs nothing and forecloses the argument. The statute permits it precisely so you can.
The same reasoning applies if you spend time in a state that does require witnesses — an Idaho-valid document is not automatically an Idaho-only document, but it is only guaranteed to satisfy Idaho.
How far this is from its neighbours
- Oklahoma: two witnesses, both must be non-legatee, non-devisee, non-heir; no notary route.
- Wyoming: notary or two witnesses who declare under penalty of perjury.
- Idaho: sign it and date it.
Three neighbouring states, and the execution requirement ranges from a perjury declaration to nothing at all.
This is the medical instrument, not the financial one
An ACPD governs health care. It does not reach money or property — that is a financial power of attorney, with separate rules.
Power of attorney requirements by state
What could not be verified
We have quoted Idaho Code section 39-4510 subsections (1) and (2). Revocation is in section 39-4511A and is not reproduced. We have not covered the health care agent’s authority, provider obligations, the registry, or how documents executed before the 2023 rewrite are treated — that last point is worth asking about if your Idaho directive predates 2023.
Related: advance directive requirements by state.
General information drawn from state statutes and official state or court forms, not legal advice. These instruments are governed by the law of the state where the property sits or the document is signed, and formalities differ from state to state — execution, witnessing and recording requirements are the parts that void a document when they are missed. Your own state’s current statute governs.