Mold in a rental: landlord or tenant?

Report it in writing the same day, with photographs, and keep a copy. Not a phone call, or not only a phone call. Almost every dispute about mold in a rental comes down to who knew what and when, and the tenant with a dated written record is in a completely different position from the tenant with a memory of a conversation.

Repairs to the building, and to anything that leaks, are the landlord’s.

The line, roughly

The landlord is generally responsible for keeping the structure and the installations in repair, and for the property being fit to live in. In practice that covers:

Leaks of any kind: roof, plumbing, windows, gutters.
Rising or penetrating damp.
A bathroom or kitchen exhaust fan that does not work, is not connected, or vents into a roof space.
Windows that will not open, or that have no trickle vents where the design depends on them.
Inadequate heating.
Insulation and cold bridging, where the building is producing condensation regardless of how it is used.

The tenant is generally responsible for using the place in a reasonable way: running the exhaust fan, opening a window when cooking or showering, not blocking vents, not drying large amounts of laundry indoors without ventilation, and heating the property to a reasonable level.

Most real cases sit in the middle, which is exactly why the record matters.

The argument you will hear, and how to answer it

The standard landlord response to mold is that it is condensation caused by lifestyle. Sometimes that is true. Often it is a property with no working ventilation, and the answer is not to argue about lifestyle but to establish facts:

Does the exhaust fan work? Hold a square of toilet paper to it. If it does not hold, film that. A fan that does not pull is a repair, not a habit.
Where does it vent? Into the attic is a defect.
Is there a leak? If the patch is damp between showers, or damp in dry weather, it is not condensation. How to tell the difference in a day.
Is it on an exterior wall in a cold corner? That is a building performance issue as much as a ventilation one.
What is the humidity? A cheap hygrometer, photographed with a date, is worth more than any adjective.

What to send, and what to keep

Send, in writing:

The date you first noticed it.
Where it is, with photographs, including something for scale.
Whether anything is leaking, and whether the fan works.
Any health effects anyone in the household is having.
A request for it to be inspected and repaired.

Keep:

A copy of everything sent, and every reply.
Dates of every visit, including the ones where nobody came.
Photographs at intervals, so the spread is documented.
Receipts for anything you buy: a dehumidifier, cleaning materials, a replacement for something ruined.

Take a fresh photograph every couple of weeks. A sequence showing growth spreading while requests went unanswered is the strongest thing you can have.

Your belongings

The landlord’s insurance covers the building and nothing you own. If mold ruins a mattress, clothes, or furniture, that is your renters policy, if you have one, or your loss if you do not.

Where the damage resulted from a defect you reported and the landlord did not repair, that starts to look like liability rather than misfortune, and the written record is the whole argument. The wider division of responsibility between landlord and tenant.

Habitability and what you can do if nothing happens

The details vary considerably by state and city, so treat this as shape rather than as your local law.

Most states imply a warranty of habitability into residential leases, and serious damp or mold can fall inside it, particularly where it affects health or where it comes with a leak that is not being fixed. Where a landlord will not act, tenants commonly have some combination of: a formal written notice with a deadline, a repair and deduct right with limits, rent escrow, a complaint to a local housing or code enforcement office, or a right to end the tenancy where the property is genuinely uninhabitable.

Every one of those has strict procedural requirements, and getting them wrong can put you in breach instead. Check your state’s tenant rights page or call the local housing office before you withhold anything.

A code enforcement inspection is often the most effective single step, because it produces an independent record that is difficult to argue with.

In the meantime

Do the things that reduce it, both because they help and because they remove the lifestyle argument:

Run the exhaust fan for twenty minutes after showering, door closed.
Open windows when cooking, and cover pans.
Do not dry laundry on radiators in a closed room.
Pull furniture a couple of inches off exterior walls.
Heat the place evenly rather than one warm room and the rest cold.
Clean small patches on hard surfaces, and keep the photographs from before. Where the size threshold is.

Do not accept an instruction to remove large areas of growth yourself. That is remediation work, and it is not a tenant’s job.

If you are the landlord

The cheap version of this is a working exhaust fan and a response within days. The expensive version is a habitability complaint, a rent reduction, and replacing the drywall in two rooms. Inspect, find the water, and fix the ventilation before arguing about the tenant’s showering habits.

The short version

Write it down the day you see it, with photographs, and photograph again every couple of weeks. Leaks and broken ventilation are the landlord’s. Test the fan with a square of paper and film it. Your belongings are only covered by your own renters policy. Check local procedure before withholding anything.