Question: I have a question about the water in my home. Anywhere there is standing water, whether it is hot or cold, mould grows. For example, the rim around the washing machine is growing black- and pinkish-coloured mould. In addition, we recently purchased a humidifier for our son's bedroom and within a few days the entire canister had grown thick, black mould. I filled it with cold tap water as per directions. Two years ago we had a new hot water tank installed, but the problem persists. We live in Transcona, in a house that was built in the 1970s. We have copper pipes, from what I can tell. Can you help us determine what the problem is, and what we can do to fix it? Do we need some type of water filter?
-- Audrey Pinette & family
Answer: Your question is a good example of something that appears to be a moderate to major concern in your home that may not be anything out of the ordinary. I will offer some advice for minimizing the mould growth, while attempting to explain the reason for its appearance.
The first thing to address is the water quality in your home, in relation to mould growth. I can say, with much certainty, that the growth of mould in your home has little to do with the water quality. Our municipal water is treated with chlorine, as well as fluoride and other processes, to prevent the growth of bacteria and other micro-organisms that can be harmful to the end users.
Moulds are present in varying quantities in most of our exterior and interior habitats and the majority are harmless or even beneficial to our health. Regardless, some types have been identified that may be potentially toxic in an indoor environment and their spores can be easily transported by indoor forced-air heating systems.
These spores may remain dormant for long periods of time, until the right environmental conditions occur that enable them to grow. For this to happen, mould needs three main things to thrive. The first and foremost requirement is moisture. The second requirement is a cellulose-based food source, and the final variable is heat.
Your perceived link between the water source and the mould growth is natural, as this component is critical for the fungus to grow. As you have stated, this can be anywhere water is allowed to remain stagnant, due to the other two requirements. If water is kept cool and moving, such as in your pressurized water pipes, there will not be sufficient introduction of heat or food for the mould to grow.
Also, airborne spores will not be able to enter the water, eliminating the possibility of growth. Once the water leaves the cool, copper water supply pipes, it will instantly begin to warm due to the ambient temperature of your home. Not only will mould spores be able to enter the water from passing air, so will other food sources. As previously stated, any cellulose-based material can be fuel for mould growth.
Most of the building materials in your home, as well as organic items, fall into this category. This may include drywall dust, pet hair, skin flakes and other small materials that regularly circulate in our homes through the forced-air heating systems. Normal household dust can contain all the food required for easy mould growth, but this will only occur if enough moisture is introduced to dormant mould spores.
The solution to your problem is not to worry about contaminants in the water, but to strive to eliminate two of the three above requirements for mould proliferation. While you don't want to remove heat from the equation, you may be able to minimize both the sources of moisture and food. It is quite common to see small amounts of mould and mildew form in washing machines and bathrooms, as they may have consistent, small quantities of standing water as well as residual soap from washing, which provides an ideal growth medium.
The first thing to do is to eliminate both the water and the soap residue. Wiping down these areas after use with a towel or rag may remove enough of these two components to minimize the problem. Allowing sufficient ventilation by opening shower doors or curtains, or the washer door, will also promote evaporation of the standing water by improved air circulation.
As for other areas in your home, avoiding excessive dust and dirt build-up will help prevent small amounts of mould from growing in areas like humidifiers and water-filled flower vases.
Additionally, the furnace filter should be changed every one to two months, especially if you have pets. Purchasing higher-quality, pleated air filters may also help reduce dust and can help trap airborne mould spores, preventing easy circulation throughout your home.
Unlike some health and safety concerns in our homes, prevention of excess mould growth may be as simple as maintaining a two-stage prevention strategy. Avoid allowing damp, poorly ventilated areas or stagnant water to develop while removing excess dust, dirt and soap scum accumulations with regular cleaning. Simply put; no water, no food, no mould.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. Questions can be emailed or sent to: Ask The Inspector, Box 69021, #110-2025 Corydon Ave., Winnipeg, MB. R3P 2G9.
