You moved in with someone who seemed perfectly normal at the inspection. They had a job, a smile, and only one mysterious duffel bag. Fast forward three months and there are strangers knocking at midnight, the milk is always gone, and your flatmate hasn’t eaten an actual meal since October. Something is off. But what?
First, a note: drug use exists on a spectrum. Plenty of people use substances recreationally and hold it together just fine. What this article is about is when it becomes a problem — for them, for you, for the lease, and for the household.
The signs worth paying attention to
Some of these will seem obvious in hindsight. Others you’ll have been explaining away for weeks.
- The three-minute visitor. In, out, no coffee, no chat. Just a knock and a brief exchange at the door. Repeat customers, odd hours.
- Loss of appetite. Their shelf in the fridge never changes. They live on cigarettes and ambient anxiety.
- The Monday disappearance. Every Monday. Off work. Curtains closed. Do not disturb. Repeat indefinitely.
- Dark rings under the eyes. Not the “busy week” look. The “haven’t slept since Saturday” look.
- Rent excuses, on rotation. “Payday is Friday.” Then Monday. Then: “can you cover me, I’ll pay you back.”
- Unusual shopping items. Straws. Sandwich bags. Tin foil — and not for the lasagne.
- Constantly asking if you have a “spare.” Whatever that means in context.
- Mood swings with no obvious trigger. Elated and chatty one day, completely invisible the next.
- Unexplained weight loss. Not the gym. Not a new diet. Just… less of them, over time.
- You’ve started locking your bedroom door. That instinct is worth listening to.
None of these signs alone confirms anything. But several of them together, in a pattern, over time? That’s worth taking seriously — for their sake as much as yours.
How to deal with it: the emotional side
Before you do anything else: check in with yourself. Living with someone whose behaviour has become unpredictable is genuinely stressful. Your instinct to avoid conflict is normal. Your frustration about the rent is valid. And your impulse to just move out and say nothing is understandable — but probably not the best first move.
- Talk to them — once, privately, and without accusation. “I’ve noticed you seem stressed lately and wanted to check in” is a better opener than “I think you’re using.” You might be wrong. And even if you’re right, a non-confrontational start leaves the door open.
- Document what’s actually happening. Rent dates missed, unusual behaviour, incidents. A simple notes app with dates is fine. If things escalate, you’ll want a record.
- Set a boundary around what’s yours. Your financial security, your safety, your mental health. These are not negotiable in the name of being a supportive flatmate.
- Don’t enable them financially. Covering rent “just this once” has a way of becoming a permanent arrangement. It’s not helping them — it’s delaying a reckoning they probably need to have.
- Talk to someone outside the house. A friend, a counsellor, a support line. You shouldn’t be carrying this alone.
Important: If at any point you feel unsafe — either from your flatmate’s behaviour or from the people visiting — prioritise your own safety above everything else. You can deal with the lease later.
Your legal rights (in plain English)
This is where most people get confused, so let’s be direct. The specifics vary by country and state, so we’ve broken this down by region.
Australia
If rent isn’t being paid
If you’re both on the lease, you’re likely jointly liable — meaning the landlord can chase either of you for the full amount. If you’re the head tenant and they’re a sub-tenant, you have more control but also more responsibility. You can issue a formal notice to remedy rent arrears once they fall behind (typically 14 days in NSW, similar in other states). Contact NSW Fair Trading, the Tenants’ Union of NSW, or your state’s equivalent body — they’re free and genuinely helpful.
If police come to your door
Police generally cannot enter your home without a warrant, your consent, or a lawful reason such as preventing imminent harm. You do not have to let them in. If they present a warrant, you should comply — but you’re entitled to read it and ask what it covers. You’re not obliged to answer questions about your flatmate. If drugs are found on the premises, you may be questioned about your knowledge of them — that’s a situation best navigated with a lawyer, not Google.
If you want them out
If they’re a sub-tenant, you as head tenant can issue written notice to vacate — but correct notice periods and grounds matter. If you’re co-tenants on the same lease, you’d need to apply to your state tribunal (NCAT in NSW, VCAT in Victoria, etc.) to have the situation resolved. Changing the locks without following proper process can backfire legally, even if their behaviour has been terrible.
Key Australian resources
- Tenants’ Union of NSW
- NCAT (NSW) — tenancy disputes
- Legal Aid NSW — free legal advice
- Drug and Alcohol Helpline: 1800 250 015 (free, 24/7)
- SMART Recovery Australia
United Kingdom
If rent isn’t being paid
As with Australia, if you’re both named on an Assured Shorthold Tenancy (AST), you’re likely jointly and severally liable. The landlord can pursue either tenant for the full rent. If you’re a lodger-head tenant arrangement, you have more grounds to act. You can serve a notice requiring payment of rent, and ultimately pursue eviction through the county court if needed. Shelter England and Shelter Scotland both offer free advice and are worth contacting early.
If police come to your door
In England and Wales, police need a warrant under the Police and Criminal Evidence Act 1984 (PACE) to enter your home without consent, unless there’s an immediate risk of harm, or they’re in “hot pursuit.” You don’t have to let them in without a warrant. You also have the right to remain silent and are not obliged to answer questions about your flatmate. Scotland has its own legal framework (Criminal Procedure (Scotland) Act 1995), but the general principle of needing a warrant applies similarly.
If you want them out
If your flatmate is a lodger (you’re the head tenant and they don’t have their own tenancy agreement), you can give “reasonable notice” — typically the length of their rental period. If they’re a joint tenant on an AST, it’s more complex: you’d need to apply to the county court or First Tier Tribunal (Property Chamber) in England. In Scotland, disputes go through the First-tier Tribunal for Scotland (Housing and Property Chamber). This process takes time, so getting legal advice early matters.
Key UK resources
- Shelter England — free housing advice
- Shelter Scotland
- Citizens Advice — housing and legal help
- Talk to FRANK: talktofrank.com — free drug advice and support referrals
- National Domestic Abuse Helpline (if safety is an issue): 0808 2000 247
New Zealand
If rent isn’t being paid
New Zealand tenancy law is governed by the Residential Tenancies Act 1986 (as updated). If your flatmate is on the tenancy agreement, you may be jointly liable for rent arrears. If they’re a flatmate under a flat-sharing arrangement (not on the primary tenancy), the head tenant has more options — including issuing a 90-day no-cause notice, or a shorter notice if there’s been a breach. Tenancy Services NZ (part of MBIE) provides free information and a dispute resolution service through the Tenancy Tribunal.
If police come to your door
Under the Search and Surveillance Act 2012, police in New Zealand generally require a warrant to enter a home unless there are specific lawful exceptions — such as preventing serious harm or where evidence is likely to be destroyed. You don’t have to let them in without a warrant. You’re not required to answer questions about your flatmate, though police may ask. If drugs or paraphernalia are found on the property, your position will be strengthened by having had no involvement — but seek legal advice if you find yourself in this situation.
If you want them out
If your flatmate is on the tenancy agreement, you’d need to go through the Tenancy Tribunal to remove them. If they’re a boarder or flatmate under a sub-tenancy arrangement, you as head tenant have more flexibility but should still follow proper notice procedures — typically 14 to 90 days depending on the grounds. Community Law Centres across New Zealand offer free legal advice, including on tenancy matters.
Key NZ resources
- Tenancy Services NZ — free info and dispute resolution
- Community Law Centres NZ — free legal advice
- Alcohol and Drug Helpline NZ
- Alcohol and Drug Helpline: 0800 787 797 (free, 24/7)
If you want to help them
Sometimes you actually like your flatmate — or at least the person they were before things got bad. If you want to try to help rather than just manage the situation, the most useful thing you can do is point them toward support without making it a condition of your relationship with them.
Ultimatums rarely work and usually create defensiveness. Something like: “I found this — it’s free and confidential — thought it might be useful” is more likely to land than “you need to get help or I’m calling the landlord.”
Most helplines in Australia, the UK and New Zealand are anonymous, free, and staffed by people trained specifically for this. None of them require a person to identify as an addict to access support. They’re also useful for people supporting someone else — you can call too.
When it’s time to go
There’s no shame in deciding that the right move is to leave — the house, the lease, the situation. Your wellbeing is not worth sacrificing for a living arrangement. If you’ve tried to address it, set boundaries, and nothing has changed, that’s not failure. That’s information.
Get proper advice on how to exit the lease cleanly so you’re not financially exposed after you go. And when you find your next place, use the interview process properly. Ask the real questions. Meet people in person. Trust your gut.
The signs are usually there from the start. We just don’t always know what we’re looking at.
flatmate.com is a share accommodation marketplace connecting people across Australia and New Zealand. Find your next place — or your next flatmate — at flatmate.com.
