The room has been empty for three weeks, the listing finally worked, and someone new moves in on Saturday. The house is delighted for about a day. Then somebody realises that nobody has actually said out loud how anything here works — and that the new person is arriving on Saturday anyway.
Most houses handle this with a cheerful "just ask if you need anything" — which sounds generous and is really a way of outsourcing every rule in the building to a stranger's guesswork.
A new housemate inherits a house they can't see
Every household runs on rules that were never written down. Bins go out Tuesday night, not Wednesday morning. Nobody showers between 7:40 and 8:00 because that is Ana's window. The blue pan is Marco's and the black one is communal. Partners stay two nights, not five, because of something that happened with a previous tenant that nobody wants to explain.
None of this is visible to the person carrying boxes up the stairs. They'll either be told or they'll guess — and every wrong guess becomes a small mark against them in a house they've known for six days. That's the quiet unfairness of joining an established share: the rules only become explicit at the moment you break one.
So a new housemate isn't an addition. It's a reset. Two weeks of deliberate effort now saves a year of low-grade friction, and the effort splits into four unglamorous parts: money, rules, the house itself, and the systems.
Settle the money before they get the keys
Do this in writing, before move-in day, while everyone is still on best behaviour. It's a fifteen-minute message that prevents the worst conversation in shared living.
- Deposit — how much, who holds it, and what it covers. If the outgoing housemate's deposit is being passed on directly, say so explicitly.
- Rent — the date it starts, whether the first month is prorated, who it goes to and by which day of the month.
- Bills — every recurring cost, whose name each account is in, the amount, when it lands, and how it's split. Include the ones you'd forget: broadband, the TV subscription, the quarterly water bill that always surprises somebody.
- Standing costs — the house kitty, cleaning products, whatever one person has been quietly buying for everyone since March.
- Furniture — whether there's a buy-in for the sofa and kitchen kit, and what they get back on the way out. Houses handle shared furniture costs very differently, so pick one and write it down.
A number said out loud in a hallway has a half-life of about four days. A number in writing doesn't.
The rules a house never wrote down are the ones a new housemate breaks first — and then gets quietly blamed for.
Write down the rules nobody ever wrote down
Ten plain lines. Not a constitution, not a laminated chart on the fridge — a short message, sent before they arrive, covering the five things that cause nearly every shared-house argument:
- Guests and partners staying over — how often, how long, and whether anyone needs a heads-up.
- Quiet hours, weeknights and weekends, and what counts as noise.
- The washing-up standard, and how long a plate is allowed to exist in the sink.
- Which food is shared and which is emphatically not.
- How cleaning is divided, and what "clean" means in this house specifically.
Send it early, and frame it as a draft rather than a decree. A new housemate who reads it and says "I'd struggle with the 10pm thing, I work late" has done you an enormous favour: that objection is free in week zero and expensive in month six.
Hand over the house, not just the room
Twenty minutes, day one, walking round together. Bin and recycling days, and where the bins actually live. The boiler, the thermostat, and how the heating schedule works. The stopcock and the fuse box. Which key opens which door, and the one that needs a lift as you turn it. The wifi password, written down somewhere permanent rather than typed once into their phone.
Then the quirks: the window that swells shut in summer, the tap that has to be turned off firmly, the neighbour who knocks about parking. Every current housemate learned these by accident. Handing them over deliberately says you live here now more clearly than any welcome drink.
Give them the landlord or agency contact too. A housemate who can report a leak themselves won't wait three days for someone else to do it.
Add them to the systems on day one
Here's where most houses lose the thread. The rules get explained, the money gets agreed — and then the new person spends two months unable to see any of it, because the real state of the household lives in one person's spreadsheet and a group chat scrolled past hours ago.
Put them into everything in week one: the house chat, the chore rota, the shared expenses, the household documents. This is what an app like Crew is genuinely useful for — a new housemate joins the household and can immediately see what's owed, what they've paid, whose turn the bathroom is, and where the tenancy agreement lives. No onboarding conversation, no trusting anybody's memory.
Do it while it still counts as admin: adding someone to the expense list on day one is paperwork, and doing it in week seven, after a bill goes unpaid, is an intervention.
Book the two-week check-in before you need it
Put fifteen minutes in the calendar for fourteen days after move-in, and hold it even if everything seems fine. Especially if everything seems fine.
Three questions: what's working, what's odd, and what did nobody explain? You'll get the small stuff — that they thought the shared shelf belonged to somebody, that they've been washing up at midnight because they weren't sure the kitchen was free — and small stuff is exactly what you want. Every long-running grievance started as something that would have taken nine seconds to say in week two.
A house isn't a set of rooms with people allocated to them. It's a working agreement that happens to have a roof. Hand the new person the agreement on the same day you hand them the keys, and by the end of the month they'll be part of the house instead of a guest who pays rent.
Frequently asked questions
What should you agree with a new housemate before they move in?
Settle the money and the rules in writing before the keys change hands. That means the deposit amount and who holds it, the date rent starts and whether the first month is prorated, which bills exist and how they are split, any standing costs such as subscriptions or cleaning supplies, and the house rules on guests, quiet hours and cleaning. None of it needs to be formal, but all of it needs to be written down, because the conversation is easy before someone moves in and awkward afterwards.
How do you add a new housemate to the bills?
Start by listing every recurring cost the house has, including the ones nobody thinks of, such as broadband, the TV subscription and the cleaning products someone buys on autopilot. For each one, note whose name the account is in, what it costs, when it lands and how it is divided. Contracts in one person's name usually stay there, so what actually matters is that the new housemate knows the amount and the date. Anything that runs on an unspoken habit, like one person always paying and never being reimbursed, should be turned into an explicit split now.
Should a new housemate pay towards furniture the house already owns?
There is no single right answer, only a right time to ask. Some houses charge a small buy-in for shared items such as the sofa, kitchen equipment and the washing machine, and refund a share when someone leaves. Others treat existing furniture as part of the room and expect nothing. Both work as long as it is agreed before move-in and written down, including what happens when the new housemate eventually moves out.
What house rules should you tell a new housemate?
Cover the five that cause almost every argument: guests and partners staying over, quiet hours on weeknights and weekends, the washing-up standard and how long dishes can sit, which food is shared and which is personal, and how cleaning is divided. Keep it to about ten plain lines rather than a full house constitution, and send it before move-in day so the new person can disagree with something while disagreeing is still cheap.
What is the easiest way to get a new housemate set up with bills and chores?
Give them access to the same shared record everyone else uses instead of explaining it verbally and hoping it lands. An app like Crew works well for this because a new housemate can be added to the household in a minute and immediately see the shared expenses, who owes what, the chore rota and the household documents. It turns the first two weeks from a memory test into something they can simply read.
