advice: should i worry about mould in my house?

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mould can cause headaches, sore throat, sinus infections and in severe cases, fevers and shortness of breath.

by maja begovic

published jul 23, 2021

last updated feb 19, 2025

3 minute read

join the conversation

3 minute read

join the conversation

mould in your home can cause a number of health issues. getty

dear asking for a friend,

i am renting an old home and there is mould in every room, it seems. the showers have a little bit of black mould in the corners (it doesn’t come off) and there is also a slimy kind of reddish mould on the tile. there’s greenish mould in the fridge (i clean it, but it comes back) and behind my bed, around the baseboards, there is black mould. should i be worried? and is there one type of mould that is worse than another?

signed, tenant

dear tenant,

according to experts, mould is a type of fungus that usually lurks in damp, old and poorly ventilated homes and buildings, and pretty much any area of the house that is dark, moist or humid creates a perfect environment for mould to form and thrive in. it’s not surprising, then, that there is mould in the bathroom or that you’re seeing evidence of it in your fridge.

a dark environment with plenty of moisture and hardly any air circulation can make mould quickly reproduce, especially if you have a habit of leaving old food in the fridge. the black-coloured mould that’s appearing behind your bed and on the baseboards may indicate a water damage issue that has been either overlooked or ignored by the homeowner.

and while most people are familiar with black mould, according to experts, there are thousands of different types of mould, which may appear as green, black, yellow, white or pink. it’s also possible for a single type of mould to embody a few different colours or present as a musty or earthy smell in the home.

there is no way to tell whether exposure to mould will have any negative health implications for you as everyone reacts to it differently. that said, mould may cause persistent headaches, sore throat, sinus infections and in severe cases, more worrisome symptoms, like fever and shortness of breath.

if you’re seeing visible signs of mould where you live, know that prolonged exposure may lead to more serious health complications, including respiratory infections and reduced lung capacity. there is some evidence that suggests that it may also impact mental health – one study found that the overall risk for depression was up to 44 per cent higher for people who lived in damp and mouldy dwellings. mould can also exasperate symptoms for those who may already suffer from other conditions.

“exposure to indoor moulds can certainly trigger allergic symptoms in those who are allergic to moulds if they have asthma, allergic rhinitis and or allergic conjunctivitis,” says dr. timothy vander leek, president of the canadian society of allergy and clinical immunology (csaci) and associate clinical professor for the division of clinical immunology and allergy, in the department of pediatrics at the university of alberta.

according to vander leek, those with asthma may experience symptoms such as coughing, wheezing, chest tightness and shortness of breath whereas those with allergic rhinitis may have to deal with nasal congestion and clear discharge, postnasal drip, sneezing, rubbing and nasal pruritus. red, itchy and watery eyes may appear for those with allergic conjunctivitis.

detecting mould can be tricky since it is not always visible and getting rid of it can be equally complicated. and while some people may attempt to scrub it off with soap and water or even bleach, which, by the way, is toxic and not recommended by experts, there are also many other diy strategies that use ingredients like grapefruit seed extract to baking soda and tea tree oil. still, mould removal should be left up to the pros, especially when you’re living in a rental property.

why not consult with a remediation service professional who can assess the situation and provide mould removal options, which should be paid for by your landlord. the added benefit of a professional evaluation is that it may uncover additional pockets of mould in the home that aren’t yet visible.

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