To file a three-party petition in Wisconsin, you need three adults willing to sign a sworn petition under Wisconsin Statute 51.20 alleging that a person is mentally ill, drug dependent, or developmentally disabled, is treatable, and is dangerous under one of five specific standards. The petition is filed in the probate court of the county where the person is physically present or legally resides, usually through that county’s Corporation Counsel office. The facts you put in the petition — specific, recent, and firsthand where possible — determine whether a judge issues a detention order within 24 hours or declines to act.
Who Can Sign the Petition
Three adults must sign, but all three do not have to be eyewitnesses. At least one petitioner must have personal knowledge of the individual’s conduct.1Wisconsin State Legislature. Wisconsin Statutes 51.20 – Involuntary Commitment for Treatment The other two can sign on information and belief, as long as the petition explains the basis for that belief — for example, a secondhand account from someone they trust who did witness the behavior.
Petitioners are typically family members, roommates, neighbors, or coworkers. Petitions carried by three people who all personally observed the dangerous behavior are stronger and tend to move faster through the Corporation Counsel review, but the statute only requires one direct witness among the three.
Wisconsin law gives petitioners who act in good faith immunity from civil liability, and good faith is presumed unless someone proves otherwise by clear and convincing evidence.2Wisconsin State Legislature. Wisconsin Statutes 51.20 Annotations – Section 51.17(4) Filing a petition you honestly believe to be true is not grounds for a lawsuit, though every signer is swearing to the petition under oath, so accuracy matters.
What the Petition Has to Allege
A diagnosis by itself is not enough. The petition must allege all three of the following: the person is mentally ill, drug dependent, or developmentally disabled; the condition is treatable; and the person is dangerous under at least one of five statutory standards. Treatability means some combination of treatment techniques could control, improve, or stabilize the condition.3Wisconsin State Law Library. Wisconsin Jury Instruction – Civil 7050
The five dangerousness standards are:
- A substantial probability of physical harm to the person, shown by recent threats or attempts at suicide or serious self-injury.1Wisconsin State Legislature. Wisconsin Statutes 51.20 – Involuntary Commitment for Treatment
- A substantial probability of physical harm to other people, shown by recent violent behavior or by evidence that others reasonably fear serious physical harm based on a recent act, attempt, or threat.1Wisconsin State Legislature. Wisconsin Statutes 51.20 – Involuntary Commitment for Treatment
- Judgment so impaired, shown by a pattern of recent acts or failures to act, that there is a substantial probability of physical harm to the person or others. This standard does not apply if reasonable community protections are available and the person is likely to use them.4Wisconsin State Legislature. Wisconsin Code 51.20 – Involuntary Commitment for Treatment
- Inability, because of mental illness, to obtain food, medical care, shelter, or safety, where without prompt treatment death, serious injury, serious physical decline, or serious disease will follow imminently.1Wisconsin State Legislature. Wisconsin Statutes 51.20 – Involuntary Commitment for Treatment
- The “fifth standard”: inability, because of mental illness, to understand or meaningfully weigh the advantages and disadvantages of medication or treatment, where the person’s treatment history and recent behavior show they need care to prevent deterioration that would cause severe harm and loss of independent functioning or control over thoughts or actions.1Wisconsin State Legislature. Wisconsin Statutes 51.20 – Involuntary Commitment for Treatment
The fifth standard is the one most commonly used for individuals with a history of psychiatric treatment who cycle in and out of care. It applies only to mental illness, not to drug dependence or developmental disability. Every standard turns on recent behavior. The statute does not define “recent” by a specific number of days, though some county Corporation Counsel offices use a practical guideline of 60 days.5Waukesha County. Three-Party Petitions (Civil Commitments)
What to Put in the Petition
The petition must include the names and mailing addresses of all three petitioners, their relationship to the individual, and the names and addresses of the individual’s spouse, adult children, parents, guardian, siblings, and anyone they live with. If any of that information is unknown, say so in the petition.1Wisconsin State Legislature. Wisconsin Statutes 51.20 – Involuntary Commitment for Treatment
Then comes the part that actually determines whether the petition succeeds: a clear, concise statement of facts establishing probable cause. Vague descriptions sink petitions. “Seems off,” “acting erratically,” or “we’re worried about him” give a judge nothing to work with. What works is specifics:
- Direct quotes of threats, with the date they were made and who heard them.
- Dates and descriptions of suicide attempts or self-harm the petitioner witnessed.
- How many days the person has refused to eat, take medication, or leave the house.
- Specific violent acts, with dates and what was seen or heard.
- For the fifth standard, a short history of past treatment and the recent behaviors showing the person cannot weigh treatment decisions.
Each signer swears to the petition’s accuracy. For the two signers relying on information and belief, the petition should name the source of that information and why the signer finds it credible.
Where and How to File
Petition forms are typically available through the county Corporation Counsel office, which is usually the practical first stop.6Langlade County. 3-Party Petition Application for Mental Illness Questionnaire Corporation Counsel attorneys review draft petitions, flag weak allegations, and prosecute the case if it moves forward. Calling that office first — rather than walking a completed petition into the courthouse cold — tends to produce a usable filing.
The petition is filed in probate court in the county where the individual is physically present or where they legally reside.1Wisconsin State Legislature. Wisconsin Statutes 51.20 – Involuntary Commitment for Treatment If the probate judge or commissioner is unavailable, the petition can go before any circuit court judge or commissioner for that county.
What Happens After You File
Once the petition is filed, the court must review it within 24 hours, excluding weekends and legal holidays.7Wisconsin State Legislature. Wisconsin Statutes 51.20(1) – Petition for Examination The judge reads the petition without the subject present (an ex parte review) and asks a single question: do the facts create cause to believe this person is mentally ill, drug dependent, or developmentally disabled and dangerous under one of the five standards based on specific recent acts, attempts, or threats?
If the judge finds the petition sufficient, the court issues a detention order. Law enforcement locates the individual and transports them to a designated treatment facility for evaluation. The court also refers the individual to the State Public Defender, who appoints counsel automatically with no financial screening.4Wisconsin State Legislature. Wisconsin Code 51.20 – Involuntary Commitment for Treatment
From there, the case moves to a probable cause hearing within 72 hours of detention (not counting weekends and holidays), and, if probable cause is found, to a final hearing where the county Corporation Counsel must prove the case by clear and convincing evidence.8Wisconsin State Legislature. Wisconsin Statutes 51.20(7)(a) – Probable Cause Hearing Petitioners can be called as witnesses. From the filer’s standpoint, the main job after filing is being available to testify to the facts you swore to.
If the judge decides the petition does not establish probable cause, no detention order issues and the case ends there. You can refile later if new behavior supports a stronger petition.
One Consequence to Know Before You File
A formal involuntary commitment order entered under Wisconsin’s 51.20 process triggers a federal firearms prohibition. Under 18 U.S.C. 922, anyone “committed to a mental institution” is prohibited from possessing, shipping, or receiving any firearm or ammunition.9Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts The prohibition is permanent absent a separate restoration process, which in Wisconsin is tied to a pardon or federal relief that has been unfunded for decades. A short-term emergency detention for evaluation is generally not treated as a “commitment” for this purpose — the prohibition attaches when a court enters a formal commitment order after the final hearing. This is worth knowing because it changes what some families expect from the process, and it is a reason the subject’s appointed attorney may push for a voluntary settlement agreement instead of a contested commitment.