- At its core, the SDA answers one question: who is legally allowed to make decisions for someone who can't make them for themselves, and how do they get that authority?
- non-continuing property POAs A power of attorney for property can be drafted as either "continuing" (it remains valid even after the grantor becomes mentally incapable) or…
- The SDA sets out specific rules about who is disqualified from witnessing a power of attorney, because a witness's independence matters.
Nearly every conversation about powers of attorney, mental capacity, or guardianship in Ontario traces back to one piece of legislation: the Substitute Decisions Act ("SDA"). It's the statute that creates Continuing Powers of Attorney for Property, Powers of Attorney for Personal Care, and the rules for guardianship when someone becomes incapable without either one in place.
Most people never read it directly, but understanding its basic shape — as part of a broader wills and estate plan — makes every related decision easier to think through: who to name as attorney, what document you actually need, and what happens if you do nothing.
What the Substitute Decisions Act Actually Does
At its core, the SDA answers one question: who is legally allowed to make decisions for someone who can't make them for themselves, and how do they get that authority? It covers two very different areas of a person's life — property and personal care — and treats them as separate legal problems with separate documents.
The Two Documents the SDA Creates
| Power of Attorney for Property | Power of Attorney for Personal Care | |
|---|---|---|
| Covers | Finances, real estate, investments, bills | Health care, housing, nutrition, safety, hygiene |
| Stays valid after incapacity? | Yes, if drafted as "continuing" | Built to operate on incapacity in the first place |
| Takes effect | Immediately, unless worded to start on incapacity | Generally once the grantor is found incapable of the relevant decision |
| Ends automatically on death | Yes | Yes |
Continuing vs. non-continuing property POAs
A power of attorney for property can be drafted as either "continuing" (it remains valid even after the grantor becomes mentally incapable) or ordinary/non-continuing (it automatically ends the moment the grantor becomes incapable — the exact opposite of when it's usually needed most). For most people planning for possible future incapacity, this distinction is the single most important line in the document.
Who the SDA Says Can't Witness a Power of Attorney
The SDA sets out specific rules about who is disqualified from witnessing a power of attorney, because a witness's independence matters. The following generally cannot act as a witness:
- The person named as attorney, or that attorney's spouse or partner
- The grantor's own spouse or partner
- A child of the grantor, or someone the grantor treats as their child
- A person whose property is under guardianship, or who has a guardian of the person
- Anyone under the age of 18
Two witnesses are required, and getting this list wrong is one of the more common reasons a homemade power of attorney later runs into trouble.
Capacity: A Legal Standard, Not a Diagnosis
The SDA treats "capacity" as a functional, decision-specific legal question — can this person understand the information relevant to this particular decision and appreciate its consequences — rather than a fixed medical label. Someone can lack capacity for one kind of decision, such as complex investment management, while retaining it for another, such as day-to-day personal care choices, and capacity can also change over time.
Guardianship: What Happens With No Valid Power of Attorney
If a person becomes incapable without ever having signed a valid power of attorney — or their existing one has lapsed or was never properly executed — the SDA's fallback is guardianship. A court can appoint a guardian of property, a guardian of the person, or both. This route is generally more involved, more public, and more costly than acting under a power of attorney that was already in place, which is the core reason planning ahead matters.
Everything Ends at Death
One rule under the SDA applies without exception: every power of attorney, for property and for personal care, ends automatically the moment the grantor dies. From that point forward, only a properly appointed estate trustee has legal authority to deal with the deceased's property — the attorney's role is over.
Frequently asked questions
Do I need both a Power of Attorney for Property and one for Personal Care?
Most estate planning for Ontario adults includes both, since they cover completely separate areas of your life and neither substitutes for the other. Whether you need both, and how they should be worded, depends on your personal circumstances.
Can the same person be my attorney for both property and personal care?
Yes, many people choose the same person for both roles, though you're also free to name different people for each if that better suits your situation.
What's the difference between a guardian and an attorney?
An attorney is chosen by you, in advance, while you're capable of making that choice. A guardian is appointed by a court after the fact, typically because no valid power of attorney exists — a more involved and more public process by comparison.
Does the Substitute Decisions Act apply to end-of-life medical wishes?
Your wishes about care, including end-of-life preferences, are generally addressed within your Power of Attorney for Personal Care, or an accompanying document, not through a separate "living will" — Ontario has no distinct legal document by that name.
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