Cohabitation Agreements in Arizona: What to Put in Writing
A cohabitation agreement is a written contract between two unmarried partners who share a home. It says who owns what, who pays for what, and how things get divided if you split up or one of you dies. In Arizona it matters more than many couples expect, because unmarried partners get none of the default protections that marriage brings. If you want those rules to exist, you have to write them yourselves. This guide covers what the agreement can do, what it can’t, and how to draft one that holds up.
TL;DR
- Arizona gives unmarried partners no automatic claim to each other’s property or estate. A written, signed agreement is the main tool for creating one.
- The contract should be in writing and signed by both of you. Oral promises are hard to prove, and some are barred outright under Arizona’s statute of frauds.
- A cohabitation agreement cannot decide custody, parenting time or child support. The court decides those based on the child’s best interests.
- Kinship guardianship is a different process, tied to children in dependency or foster care, and it is not something a partner contract can replace.
- Have an attorney draft it, and pair it with a will or beneficiary designations.
Table of Contents
- Why unmarried couples need a written agreement in Arizona
- What a cohabitation agreement can cover
- What it cannot do: children
- How to make the agreement enforceable
- Cohabitation agreement, prenup or marriage?
- Perspective: what we tell couples who call us
- Kinship guardianship: a different question
- When we can help
- FAQ
- Sources
Why unmarried couples need a written agreement in Arizona
Marriage comes with a built-in rulebook. Arizona is a community property state, so property acquired during a marriage is generally shared, and a divorce court has defined tools to divide it. Living together does not trigger any of that. When an unmarried couple separates, property generally belongs to whoever holds title, whose name is on the account, or who can prove a contract or ownership claim.
That gap shows up in ordinary situations:
- One partner moves into a home the other owns and spends years paying the mortgage, taxes or renovations.
- Two partners buy a house together, but one puts in most of the down payment.
- One partner leaves a career to raise a child or support the other’s business.
- One partner dies with no will, and the survivor discovers the law doesn’t treat them as family.
A cohabitation agreement replaces guesswork with terms you both chose while you still get along. That is its real value. Negotiating fairness is far easier before a breakup than during one.
What a cohabitation agreement can cover
Think of the agreement as a map of your shared finances. A well-built one usually addresses these areas.
Property you bring in and property you acquire
List what each of you owns now: a home, a car, savings, retirement accounts, a business. State that it stays separate. Then decide how you will treat things bought during the relationship. Options include splitting by contribution, splitting equally, or keeping anything titled in one name as that person’s alone.
The shared home
This is where most disputes land. The agreement should say who is on the title, what each person has paid toward the down payment, mortgage, insurance and repairs, and what happens if you separate. Common solutions include one partner buying the other out at an appraised value, a forced sale with proceeds divided by a set formula, or a deadline for one person to move out.
Because real property is involved, put it in writing. Arizona’s statute of frauds bars suits on certain agreements, including those that can’t be performed within a year and those involving interests in real property, unless the promise or a memorandum of it is written and signed by the party being held to it.
Day-to-day expenses and debts
Decide how rent, utilities, groceries and insurance are split, whether by percentage of income or equal shares. State that each partner remains responsible for debts they bring in or take on alone. Say what happens to jointly signed debts such as a car loan or credit card.
Support during or after the relationship
Some couples agree that if one partner gives up income, the other will pay a defined amount for a set period after a breakup. Others waive any claim. Either is a contract term rather than something the law supplies by default, so it has to be clear and specific.
Death, incapacity and the estate
Under Arizona’s intestacy statutes, the surviving spouse has a defined share of the estate under A.R.S. § 14-2102. Other heirs are then identified under A.R.S. § 14-2103, and those categories are built around spouses and family, not live-in partners. If you die without a will, your partner could end up with nothing from your estate.
An agreement can set out your intentions, such as the right to stay in the home for a period. But a will, a trust, and beneficiary designations on retirement accounts and life insurance are the documents that actually move assets. Treat the cohabitation agreement as one piece of a set, and ask an attorney to line them up so they don’t contradict each other.
What it cannot do: children
This is the most common mistake we see couples make in drafts they find online. Parents sometimes write custody schedules, decision-making rights or child support figures into a cohabitation agreement. Those terms will not bind a court.
Arizona courts decide legal decision-making and parenting time on the child’s best interests, and appellate courts treat those questions as ones the court controls. See, for example, this Arizona Court of Appeals opinion on how the statutory rules for changing decision-making or parenting time apply when a parent seeks to relocate. Child support likewise follows state guidelines, not private bargains. Parents can still cooperate and propose a plan to the court, but the judge reviews it.
If you and your partner have a child together, the practical steps are different:
- Establish paternity if it has not already been established.
- File for legal decision-making and parenting time so you have a court order.
- Build a parenting plan the court can approve.
Our guides on parenting time in Arizona and legal decision-making factors walk through that process. A cohabitation agreement can still deal with the adults’ finances around the child, such as who owns the family home, but it can’t set the child’s terms.
How to make the agreement enforceable
A contract is only as good as your ability to prove it and a court’s willingness to enforce it. These habits help.
- Put it in writing and both sign. The statute of frauds is one reason; proof is the other. A handshake deal about a house is a lawsuit waiting to happen.
- Disclose your finances honestly. Attach a schedule of assets, debts and income. Hidden assets give a judge a reason to doubt the agreement.
- Be specific. “We’ll split things fairly” settles nothing. Use percentages, dollar figures, dates and formulas.
- Get separate advice. Each partner should ideally have their own lawyer. It is much harder to claim you were pressured or didn’t understand a document that independent counsel explained to you.
- Sign without pressure. Don’t hand it over the night before a move or a closing.
- Update it. Buying a home, having a child, starting a business or a major inheritance should all trigger a review.
- Keep records. Save bank statements, closing documents and receipts that show who paid what.
One comparison is worth knowing. Arizona’s premarital agreement statute, A.R.S. § 25-202, requires a written agreement signed by both parties and makes it enforceable without consideration. That statute is written for people who are about to marry, not for cohabiting partners. A cohabitation agreement is an ordinary contract, which means contract rules such as clear terms and mutual agreement carry more weight.
Cohabitation agreement, prenup or marriage?
| Cohabitation agreement | Prenuptial agreement | Marriage with no agreement | |
|---|---|---|---|
| Who it’s for | Unmarried partners living together | Couples about to marry | Married couples relying on state default rules |
| Governs property | Only as you write it | As you write it, within the law | Community property rules apply by default |
| Inheritance without a will | No automatic rights | Spousal rights unless waived | Spousal intestate share |
| Controls custody or child support | No | No | No |
| Ends how | Terminates by its own terms or by mutual agreement | Applies at divorce or death | Through divorce or death |
The table points to a decision many couples overlook. If you plan to marry eventually, the cohabitation agreement can bridge the years before the wedding, and a prenuptial agreement can then follow. If you never plan to marry, the cohabitation agreement is your main protection.
If you do later marry, you may want a new agreement. A cohabitation agreement isn’t designed to govern marital property, so ask an attorney whether it should be ended, replaced or carried into a premarital or postnuptial agreement.
Perspective: what we tell couples who call us
At our firm we spend our days after relationships have ended, and the pattern is consistent. The couples who come through a separation with the least damage are almost never the ones with the best intentions. They are the ones who wrote things down.
We’ve represented families in Scottsdale for more than 20 years, and the most expensive disputes we see are not about large estates. They are about a house, a car or a bank account where each person remembers a different promise. A short, clear contract settles those arguments before they start.
Three pieces of advice from our side of the table:
- Draft it when you’re happy. It feels awkward to discuss a breakup while you’re planning a future. It is much more awkward in a courtroom.
- Keep children out of it. Protect your kids by getting proper court orders for custody and support, not by trying to squeeze them into a contract the court will set aside.
- Match your documents. Your agreement, will, beneficiary forms and deed should say the same thing. Mismatches cause more fights than missing paperwork does.
If you are still weighing marriage, mediation or a more formal separation of finances, we are glad to talk through how the options fit your situation.
— Brett
Kinship guardianship: a different question
Some readers who search for cohabitation agreements are actually trying to sort out a different arrangement: a grandparent, aunt or family friend who is raising a child. A partner agreement does not give you legal authority over a child who isn’t yours.
Arizona’s Court system notes that kin lack an automatic legal relationship to the children they raise, and that getting one can be costly and slow. Without it, caregivers may struggle to get services and support for the child.
There are two broad paths:
- Kinship foster care through the Department of Child Safety. DCS describes kinship foster care as placement with relatives or people who have a significant relationship with the child.
- Permanent guardianship. A.R.S. § 8-871 lets a court grant permanent guardianship of a child. Among its conditions, the child must be adjudicated dependent or be the subject of a pending dependency petition, and the child must have been in the prospective guardian’s custody for at least nine months, though the court may waive that for good cause.
A different path exists for relatives not involved with a dependency case. You can ask the court for guardianship or, in some cases, other relief. Because the right route depends on the child’s situation, speak with a family law attorney before filing anything. Our family law practice handles guardianship and grandparent petitions.
When we can help
We represent individuals and families across Scottsdale and the surrounding area in divorce, custody, paternity and related matters. If your relationship involves children, a shared home or a past agreement that has gone wrong, we can help you figure out where you stand.
- If you have a child with your partner, see our child custody practice.
- If you are planning to marry, or already married and thinking about restructuring finances, our divorce and family law team can explain how marital property differs from what you have now.
- If you need a neutral process to end a relationship on agreed terms, ask about divorce mediation.
We do not publish fixed prices, so ask us for an initial conversation about your situation. You can start at highdesertfamilylawgroup.com.
FAQ
Is a cohabitation agreement legally binding in Arizona?
Yes, when it is a written contract signed by both partners with clear terms and honest financial disclosure. Courts look at it as they would any other contract. Terms that involve children’s custody or support are not binding on the court, no matter what you wrote.
Does Arizona recognize common law marriage?
No, Arizona does not allow couples to create a common law marriage inside the state, no matter how long you live together. Arizona generally honors valid marriages formed elsewhere, so a couple who formed one in a state that allows it could be treated as married. If you aren’t sure whether this applies to you, ask an attorney before relying on it.
Can I inherit from my partner without a will?
Not under the intestacy statutes. Arizona’s intestate succession rules focus on a surviving spouse and family members, so an unmarried partner would likely receive nothing. A will, a trust, or named beneficiaries on accounts is how you provide for a partner.
Can we put custody and child support in the agreement?
You can write down your intentions, but the court will not be bound by them. Arizona courts decide parenting time and decision-making based on the child’s best interests. If you share a child, get a court order, and see our guide to joint custody in Arizona.
Does a cohabitation agreement replace a will?
No. It sets out your understanding as partners, but a will, trust and beneficiary designations are what direct your assets at death. Use them together so they say the same thing.
Sources
- A.R.S. § 44-101, Statute of frauds
- A.R.S. § 14-2102, Intestate share of surviving spouse
- A.R.S. § 14-2103, Heirs other than surviving spouse
- A.R.S. § 25-202, Enforcement of premarital agreements
- A.R.S. § 8-871, Permanent guardianship of a child
- Arizona Court of Appeals opinion, 1 CA-CV 15-0170
- Arizona Kinship Legal Toolkit training slides
- Arizona DCS, Resources for Kinship Foster Caregivers
