Whose names go on the deed and the loan, what each person's money counts as, how to split the monthly bills, and how anyone gets out later.
Families who share a house well settle the money in writing before they move in, while everyone still agrees. The deed says who owns the house. The mortgage says who owes the lender. Those are separate decisions, and it is common to get one right and forget the other.
Every dollar a parent or child puts in is a gift, a loan, rent, a buy-in or a share of the bills. The IRS, a lender and Medicaid each treat those differently, so decide which it is and write it down. Then agree now on what happens when someone wants out, needs more care, or dies.
In 2021, 59.7 million Americans lived in a multigenerational household, 18 percent of the population, according to the Pew Research Center. In 2025, 14 percent of home buyers bought a home for more than one generation, most often to care for an aging parent or to save money, according to the National Association of Realtors.
Most families get there by one of five routes. Each one puts the money risk in a different place.
| The setup | Who usually owns the house | What to settle first |
|---|---|---|
| A parent moves into your house | You | Whether the parent pays rent, shares the bills or pays for changes to the house, and what that money counts as. |
| You move into a parent's house | The parent | Whether you are a tenant, a caregiver or a future owner, and what your brothers and sisters expect to inherit. |
| You buy a house together | Everyone on the deed, in shares you choose | How the shares reflect the down payment, who is on the loan, and the buyout terms. |
| A parent pays for an addition or an ADU on your house | You, unless the deed changes | Whether the parent is buying a share, buying the right to live there, or giving you money. This setup causes the most Medicaid trouble. |
| A parent sells their house and moves in with the proceeds | Depends on where the sale money goes | Whether that money is still the parent's on paper, or has become part of your house. |
Brothers and sisters who are not moving in still have a stake. When a parent's savings go into one child's house, everyone else's inheritance changes. Share the terms before anyone signs, and keep them somewhere the whole family can see.
The deed decides who owns the house. The mortgage note decides who owes the lender. A parent can be on the loan without owning any of the house, which means carrying the debt with none of the equity. A parent can also own a share without being on the loan at all.
| Form | What it means | Worth knowing |
|---|---|---|
| One owner | One person owns the house and the others live there. | Simple. Anyone else's money in the house then needs its own paper: a loan note, a lease or a written agreement. |
| Joint tenants with right of survivorship | Owners hold equal shares. When one dies, the others own the house automatically, without probate. | Shares are equal no matter who paid what. A parent's share goes to the other owners on the deed, whatever the parent's will says. |
| Tenants in common | Each owner holds a stated share, such as 70 and 30. Each share passes through its owner's will or trust. | Fits unequal contributions. Put the shares on the deed and plan who inherits each one. |
| A trust or an LLC | A trust or company the family controls owns the house. | Can suit a larger arrangement. It adds cost and paperwork and can affect the mortgage and homestead tax breaks, so ask an attorney first. |
Lenders look at everyone who signs the note. A few rules matter for families buying together:
Every borrower on the note owes all of it. A late payment shows on every borrower's credit, and the lender can collect from any of them. A parent who co-signs should see the statements.
Every dollar that goes into the house becomes one of five things. Pick one on purpose and put it in writing. If the paperwork does not say, the IRS, the lender and a Medicaid caseworker will each decide for you, and they may not decide the same way.
| If it is | Put this in writing | How it is treated |
|---|---|---|
| A gift | A signed gift letter with the amount and the date. | Gifts above the annual exclusion, $19,000 per person in 2026, need a federal gift tax return (Form 709). Tax is rarely owed, because the lifetime exemption is $15 million per person in 2026. For Medicaid, a gift made within the look-back period, five years in nearly every state, can delay coverage. |
| A loan | A promissory note with the rate, the payments and what happens if the lender dies. Record it against the house if it should be secured. | A family loan over $10,000 should charge at least the IRS applicable federal rate. Otherwise the IRS can treat the skipped interest as a gift to the borrower, and in some cases as taxable interest to the lender. For Medicaid, a loan counts as a gift unless the payments are equal, the term fits the lender's life expectancy, and the balance does not cancel at death. |
| Rent | A written lease or rental agreement with the amount. | Rent is income to the owner. Rent below the going rate from a relative limits what the owner can deduct against it. A parent paying fair rent is not making a gift. |
| A buy-in | The deed showing the new owner's share, or a written co-ownership agreement. | The money buys a share of the house. If a parent instead buys a life estate, the right to live in someone else's home for life, Medicaid counts the price as a gift unless the parent lives there for at least a year after buying it. |
| A share of the bills | The monthly split, written down. | Paying a fair share of groceries and utilities in the home you live in is ordinary household spending. Paying far more than your share, or paying the owner's mortgage, can be counted as a gift to the owner. |
Pay by check or bank transfer from the account of the person whose money it is, with a memo that matches the paperwork. Cash and shared accounts are hard to explain five years later, which is exactly when Medicaid asks.
Most tension in a shared house comes from the monthly money, and most of that comes from a split nobody chose on purpose. Sort the costs into two piles first.
Then choose how to divide each pile. Families usually use one of these methods, or one for each pile.
| Method | How it works | Suits |
|---|---|---|
| Equal per adult | Divide the total by the number of adults. | Similar incomes and similar use of the house. |
| By income | Each adult pays the same percentage of their income. | Very different incomes, such as a parent living on Social Security. |
| By ownership | Owners pay the house costs by their share of the deed, and everyone splits the household costs equally. | Families where one person owns more of the house than the others. |
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| Adult | Equal per adult | By income | By ownership |
|---|
Open one checking account for shared costs. Each person transfers their share on the same day each month, and the bills are paid from that account. It keeps a clean record for everyone, and nobody fronts money and waits to be paid back.
Agree on the difference now. A new water heater keeps the house as it was, so it is a repair. A new kitchen adds value, so it is an improvement. Set a dollar amount above which spending needs everyone's agreement, and decide whether an owner who pays for an improvement gets that money back first when the house sells.
The person who drives to appointments, manages medications and is home at night is contributing something with real value. Decide whether that care is given freely, credited against their share of the costs, or paid.
If a parent pays a family caregiver, use a written personal care agreement at a fair local hourly rate, signed before the care starts. Without one, Medicaid can treat the payments as gifts. The caregiver reports the pay as income.
These rules tend to surface years later, when a parent needs nursing home care, an owner dies, or the house is sold. Take the plan to an elder law attorney and a tax preparer before any money moves.
Every shared house ends somehow. Settle the terms while everyone agrees, because by the time you need them, someone is grieving, sick or angry.
| When this happens | Decide now |
|---|---|
| Someone wants to move out | How much notice they give, how their share is valued, how long the others have to buy it, and whether the house must be sold if nobody can. |
| A parent needs more care than the house can give | Whether the parent's share is bought out or kept, how the care is paid for, and who manages the parent's money. |
| An owner dies | Who inherits their share, whether the people living there can stay, and how the others buy out heirs who do not live there. |
| A marriage ends | Whether a son-in-law or daughter-in-law has any claim to the house or to a parent's contribution. A prenuptial or postnuptial agreement, or clear records of separate property, can settle it in advance. |
| Someone cannot pay their share | How long the others cover it, whether it becomes a loan, and when it changes the ownership shares. |
| The house is sold | The order the money comes back: family loans first, then each owner's down payment and agreed improvements, then the rest by share. |
Pick the method now. One appraisal by an appraiser everyone agrees on, the average of two appraisals, or a written formula all work, as long as it is chosen in advance. Set a buyout window, such as six or twelve months, and a right of first refusal, so the others get the first chance to buy a share that is leaving.
The document is usually called a co-ownership agreement, or a family or household agreement. An attorney in your state can draft it or review yours. It should cover who owns what share and why, what each person's money is, the monthly split and the house account, repairs and the approval amount, care and whether it is paid or credited, every exit term above, and how disagreements get settled, such as a family meeting first and a mediator second.
Then make the other documents match it. Wills, trusts, powers of attorney, health care proxies and beneficiary forms should all say the same thing as the agreement. A will cannot override a joint tenancy deed.
Meet monthly for the first few months, then every quarter. Go through the house account, repairs coming up, anything that has changed about health or care, and anything that is bothering someone. Review the whole agreement once a year, and whenever someone's health, job or marriage changes.
The Multigenerational Home Kit has nine worksheets: the household and the plan, what each person puts in, the deed and the mortgage, taxes and Medicaid, the monthly split, care and chores, living together, the exit plan, and the family meeting.
Download the Multigenerational Home Kit (PDF)Paper goes stale. Hubstone holds the same record and keeps it current, and you choose who sees each page.
General information, not legal, medical or financial advice. Requirements differ by state.