Signs of Water Damage and Mold

Tips for Identifying the Warning Signs of Water Damage

Water damage can be a nightmare for any property owner. Saturated carpets, waterlogged belongings, and even mold are all possibilities after a property has a water leak or experiences a flood. However, not all water damage is created equal. This article will help break down the signs of water damage a property owner should look out for, as well as the different causes and types of water damage that can occur.

What Causes Water Damage?

Water damage can occur as the result of several different scenarios. It is important to understand these various causes, and the differences they can each mean for insurance purposes and for the recovery process.


A flood is a situation in which water rises and covers dry land. This could be because of a river overflowing its banks, a storm surge from a hurricane, a substantial amount of runoff from snowmelt, the mechanical failure of a dam or levee, or a combination of these issues. The important factor is that the source of water is outside the building and, in most cases, naturally occurring. Damage caused by flood water may not be covered by insurance unless a flood rider has been added to the policy.

Burst or Leaky Pipes

The most frequent cause of water damage from within buildings is water coming from the building’s pipes. The most common causes of this type of damage are:

  • Frozen pipes – As temperatures drop, water in a pipe can freeze. This freezing causes the water to expand, putting extreme pressure on the pipes and plumbing joints, and sometimes causing them to crack or burst. Once the frozen pipe thaws, water can begin dripping or streaming out of pipes and into basements, bathrooms, or even walls and ceilings.
  • Mechanical failure of pipes – With the improvement in quality and strength of pipes over the years, most modern pipes will not simply fail due to age or use. These failures are mostly the result of improper installation, the use of improper materials for a particular application, or a manufacturing defect.
  • Other mechanical failures – Sprinkler systems, washing machines, and other mechanical systems that use water are also a potential source of water damage. For example, one of the most frequent causes of water damage in hotels is guests hanging clothing on the room’s sprinkler heads, damaging them and causing water to flow freely from the system and into the room.

Categories of Water Damage

When it comes to water damage, there are three categories to know. These categories are based on the source of the water and the potential for harm that it carries.

  • Category 1: This is water that has come from a source such as the clean water supply in a home. If addressed within 24-48 hours, most Category 1 water poses a low health risk. However, even clean water can begin to cause mold in as little as 48 hours.
  • Category 2: This category is known as “gray water.” This water comes from sources that could have mild to severe contamination, including fire suppression systems, treated cooling water lines, and discharge from equipment. Caution should be exercised around Category 2 water. Materials exposed to Category 2 water may not be salvageable.
  • Category 3: “Black water” – highly contaminated, dangerous water that carries a significant risk of disease, infection, and irreparable damage. Sources of black water include sewers, drain backups, and water that has overflowed from rivers, lakes, or the sea. Extreme caution should be exercised around Category 3 water. Most materials exposed to Category 3 damage will likely need to be replaced.

Download Your Water & Flood Resources

Be prepared. Click here to download your water and flood guide and checklist.

Signs of Water Damage

It is important to watch for signs of water damage and investigate them as soon as possible to catch minor issues before they become significant damage. Knowing where to look and what to look for can help identify damage before it gets worse. Some general early signs of water damage in homes or commercial buildings include:

  • A sharp increase in the water bill
  • A loss of water pressure
  • Seeing or hearing dripping water
  • The presence of standing water on floors
  • Musty, moldy smells
  • Stains and streaking

Signs of Water Damage in Walls

Because many of a building’s pipes run inside the walls, there is a risk of water damage to these areas. A burst pipe can cause water to leak into the wall cavity, soaking the building materials and insulation. Water can also enter these spaces from the outside if a building’s envelope is not properly sealed.

Signs of water damage to a building’s walls can include:

  • Bubbling or running paint on the walls
  • Swollen, soft, or crumbling drywall
  • Swollen baseboards or mouldings
  • Dark staining behind wallpaper
  • Streaking on the surface of the wall
  • Streaks or discoloration around windows, doors, vents, or air conditioning units

Signs of Water Damage on Ceilings

In many buildings, pipes and HVAC ductwork run through the ceiling spaces, putting these areas at risk of water damage. Over time, accumulated water from a leaking pipe or condensation from HVAC ducts can lead to water damage. Other potential causes can include water infiltration from ice damming or clogged drains on the building’s roof.

Important signs of water damage on a ceiling include:

  • Sagging or discolored ceiling tiles or areas of ceiling drywall
  • Discolored spots on the ceiling or individual tiles
  • Soft, swollen, or crumbling drywall

Signs of Water Damage in Kitchens

Kitchens include a significant amount of plumbing, from sinks and dishwashers to ice maker water supply lines. Any damage to or leaks from these plumbing lines could cause water damage to walls, cabinets, and floors.

Signs of water damage in kitchens to look out for:

  • Discoloration in under-sink cabinets
  • Swelling of cabinet doors and gable ends
  • Moisture around refrigerators and freezers
  • Swelling of wood floors
  • Peeling vinyl floor tiles

Signs of Water Damage in Basements

Because of gravity, water that floods or leaks into a building will find its way to the lowest point it can reach. In many cases, this is the basement of the building. Basement spaces also frequently contain plumbing, HVAC equipment, washing machines, and other systems that can fail and cause leaks. Because these spaces are often unoccupied, leaks and water damage may not be detected for some time.

Some important signs of water damage in basements:

  • Discoloration on floors
  • Cracks or streaks on walls
  • Standing water in elevator pits or parking garages
  • Sump pump running frequently

Signs of Water Damage to Foundation

The foundation serves as a barrier to prevent groundwater from infiltrating a building. When soil is supersaturated, hydrostatic pressure can force groundwater into spaces that are not properly sealed or waterproofed.

Signs of water damage to the foundation include:

  • Cracked or crumbling cement or cinder blocks
  • Water accumulation around the perimeter of basement spaces
  • Discoloration, streaking, or mold on walls

Signs of Water Damage in Bathrooms

Pipe clogs, drain backups, frozen plumbing, poor ventilation, and a number of other causes can lead to water damage in a bathroom. Because these spaces are exposed to so much water and humidity, they are at a higher risk of water damage.

Signs of water damage in bathrooms can look like:

  • Discoloration in under-sink cabinets
  • Swollen baseboards or mouldings around toilets, sinks, and showers
  • Condensation on ceiling, walls, and floors
  • Peeling vinyl wall and floor coverings

Concerned About Potential Water Damage?

If a property owner suspects there may be water damage in their building, it is important to address the issue right away. Because of the potential health risk that can be posed by some types of water, and because of the risk of mold, it is best to contact a trusted recovery partner like First Onsite to help identify water damage and safely guide the mitigation and repair processes. First Onsite has a wealth of experience locating and repairing water damage, and can make use of tools like thermal imaging cameras to locate water inside wall cavities that may not be detected by a property owner until it is too late.

Water & Flood Resources

Be prepared, download today

Water & Flood Guide Water & Flood Checklist

Sign up for Updates