Home > Maintenance & Renovation > The Ultimate Guide to Water Damage in Your Home (2023)

The Ultimate Guide to Water Damage in Your Home (2023)

Updated Jan 9, 2023

Updated Jan 9, 2023

Home > Maintenance & Renovation > The Ultimate Guide to Water Damage in Your Home (2023)

Water damage is one of the worst scenarios a homeowner can encounter. Water damage can spread toxic mold spores, ruin appliances and furniture, and even result in collapses and structural hazards. If you discover a flooded room, you will need to act immediately to quell the source of the leak and mitigate as much damage as possible.

This guide will break down all the significant elements of water damage, including its causes, hazards, and the immediate steps you should take to resolve it. 

Identifying Your Water Category and Class of Damage

The Institute of Inspection Cleaning and Restoration Certification (IICRC) uses two metrics to assess water damage: water category and class of damage. The water category refers to the type of water introduced to an affected area, with each category reflecting the hazardous materials within the water. The higher the water category, the more unsanitary it is and the more dangerous it is to handle. The water damage class reflects the amount of water introduced to a location and how difficult it is to remove. 

Understanding the classifications and categories of water damage is essential, as not all types of leaks are manageable on your own. Even smaller, lower classification leaks, if they are of a high enough category, can be highly toxic and should only be handled by professionals. On the other hand, even completely clean water, if in a high enough classification, can damage the home’s structure so much as to require restoration services. 

What Are the Different Categories of Water? 

Domestic water falls into three categories, some of which have respective subcategories: Category 1 (clean water), Category 2 (greywater), and Category 3 (blackwater). 

Category 1: Clean water

Clean water, as its name implies, is water with little to no hazardous materials. This water is the safest and is manageable by homeowners in small to moderate amounts. While usually only the cause of minor damage, in large enough quantities, it can still cause significant damage to house structures, furniture, and appliances. While also relatively clean, if not managed and removed correctly, it can turn into greywater and then blackwater quickly (within 24 to 48 hours). You most often see Category 1 water damage from the following sources: 

  • Rainfall 
  • Leaky pipes 
  • Broken appliances 
  • Toilet tanks 
  • Faucets 
  • Snowmelt 
  • Leaky roofs
  • Damaged sprinklers 

Category 2: Greywater 

Greywater, sometimes spelled graywater, is a type of wastewater produced mainly from appliances. It contains minor contaminants such as a dishwasher’s food particles or less hazardous chemicals from appliances. These contaminants make the water less safe to handle than clean water and dangerous to ingest, but still safe enough for homeowners to clean on their own. Greywater has two subcategories, dark and light greywater, differentiated by the water source and the hazardous materials within that source. 

  • Light greywater: This is the less dangerous of the two and comes from showers, water basins, tubs, and clothes washing machines. Light greywater contains chemicals like detergents or soaps. 
  • Dark greywater: This type of greywater contains food particles and more dangerous chemicals. Dark greywater comes from dishwashers, kitchen sinks, mop sinks, and so forth. 

In small amounts, greywater is cleanable at home, but in large quantities can turn into more dangerous blackwater in less than 48 hours. If you decide to clean greywater at home, wear thick rubber gloves, eye protection, a face mask, and rubber boots if the water is above ankle-deep.

Category 3: Blackwater 

Blackwater is the most dangerous type of domestic water you can encounter. Blackwater contains dangerous pathogens, chemicals, and other hazards, making it unsafe to handle without the proper gear and training. Due to its high contamination levels, blackwater is not manageable by homeowners under any circumstances. Blackwater can lead to rapid, toxic mold growth and should be removed by a professional immediately. Sources for blackwater leaks include: 

What Are the Different Classes of Water Damage?

The next factor in water damage assessment is the class of damage. Water damage classification reflects the amount of water allowed to seep into an affected area, the water’s contents, and how difficult the water is to remove. The higher the classification, the more water, the nastier the water is, and the harder it will be to remove. 

Class 1

Class 1 refers to rooms that have been partially affected by water damage and are the lowest classification. Minor leaks, such as dripping pipes, or rooms with a low amount of porous substances, often constitute most Class 1 incidents.   

Class 2 

The second class of water damage reflects medium-sized leaks and rooms with moderate amounts of porous materials. Rooms with carpet, drywall, and wooden floors affected by a broken pipe would fit into this category. This class covers situations where the water has wicked up the wall 2 feet or less, has absorbed into the entirety of the carpet, and begun to seep into the surrounding construction of the room. 

Class 3

This class represents when the water has thoroughly soaked into the construction and support materials of the room or where the water has wicked up higher than 2 feet. When structures such as the subflooring, ceilings, flooring, floor coverings, and gypsum have absorbed considerable water, the damage reaches Class 3. This class is often the result of minor floods, significant leaks from upper floors, and damaged or ruptured water lines.

Class 4

Class 4 is the final level of water damage and is the most damaging. When water becomes bound (or trapped) in significant areas of the room’s construction, the damage becomes Class 4. This class represents the most challenging water damage to remove, as the water is in difficult-to-clean areas and requires special equipment to clear. Some examples of Class 4 water damage include water getting trapped inside sections of a wall, a hardwood floor absorbing water to its core, and water getting behind built-in cabinets. 

What Are the Major Causes of Water Damage?  

Water damage can result from numerous causes, some more common than others. If you spot early signs of water damage (such as spots on the ceiling, warped floorboards, or cracking and bubbling of paint), you should always try to find and eliminate the cause. Even if the damage is minor, it can spread, or the source may build up and become a more significant leak. 

Leaky Pipes 

Leaking pipes are one of the most common causes of minor water damage. On their own, leaky pipes cause little harm, but they can be signs of more significant problems down the road. A leaky pipe can be caused by water pressure issues, the pipe’s materials degrading, poor seals, or climate-induced conditions like freezing. 

Broken Appliances 

Another common cause of water damage is broken or faulty appliances. From dishwashers to washing machines and even water heaters, these tools can burst and flood rooms if not maintained. Be sure to always keep an eye on your appliances and have them inspected if they begin to malfunction or act strangely. 


Floods are less likely to occur than other culprits on this list, but when they do happen, they can be devastating. Floods introduce the most dangerous kind of water to your home, potentially in massive quantities. Even a minor flood can ruin entire portions of a home, and to make matters worse, they are typically not covered under most homeowners insurance policies. If you live in an area prone to floods, your best bet is to seek out a separate insurance policy against flood and mold damage, keep an eye on weather reports, and prepare accordingly. 

Clogged or Otherwise Broken Gutters 

Clogged gutters are a cause of water damage that homeowners often overlook. Gutters funnel and redirect rainwater away from the home’s foundation and walls. This system helps keep your lawn, foundation, siding, and walls free of water damage. If your gutters become clogged, they cease to function, leading to water damage outside and inside the home. Be sure to clean your gutters at least twice yearly and repair or replace damaged sections immediately. 

Leaky Roof 

Your roof, like your gutters, is designed to protect more susceptible areas of the home. Your roof shingles are coated in a waterproof asphalt coating, followed by an underlayment that keeps moisture out. When these systems fail, water can seep into the roof structures, down into your insulation, and then into the ceiling. To stop roof leaks before they can cause severe damage, you should keep an eye out for signs of a damaged roof, such as: 

  • Curled shingles 
  • Missing shingles 
  • Clogged valleys 
  • Moss growing between shingles 

Severe Weather

Thunderstorms, hail, hurricanes, and even high winds can cause damage to shingles, siding, and other home sections designed to keep water out. When this happens, your home can become susceptible to water damage. Severe rainfall can also cause immediate water damage if drainage systems cannot quickly redirect the water. Severe weather is challenging to prepare for and plan against, as heavy storms can occur spontaneously. The best practice for homeowners is to ensure that their water drainage systems (like gutters, storm drains, etc.) are functioning correctly and that the roof, siding, and other structures are well maintained. 

Clogged Drains 

Clogged drains in the kitchen and bathroom are among the most common causes of indoor water damage. These clogs result from hair, grease, dirt, and debris buildup. Eventually, these materials clog the drain enough to prevent water from passing through, overflowing, and causing damage. To prevent this, make sure your drains are funneling water properly, and if you suspect a drain is experiencing a clog, don’t put off cleaning it. 

Damaged or Burst Utility Pipes 

The pipes that carry water into the home are designed to be long-lasting and durable. But these systems are pressurized to direct water to the appliances and features that need it. This pressure can degrade these utility pipes over time and, in the case of a fault or damage, cause severe ruptures that can spread water very quickly. Before a full-on burst, there are several signs of a leaking or faulty water main you can keep an eye out for: 

  • Discolored water 
  • Low water pressure 
  • “Hissing” sound coming from pipes 
  • Bubbling sound coming from pipes 
  • Foul-smelling water 
  • Puddles of water in and around the home 

Damaged Sprinklers

Damaged sprinklers can result in a spectacular display, sending water over a dozen feet into the air. What isn’t spectacular is the damage this causes to your lawn. A broken sprinkler head or damaged pipe can result in severe water damage to your foundation, not to mention an overly moist yard, which can attract pests. To avoid this, be sure not to set your mower deck too low when mowing, and thoroughly inspect your sprinkler system yearly during the spring.  

What To Do if You Discover a Leak

Finding an active leak or flooding situation in your home can be shocking or, depending on the size of the leak, terrifying. But by keeping a cool head and following these simple steps, you can quickly stop the leak and mitigate the amount of damage it can do. 

Assess Immediate Dangers and Safety Hazards

Leaks can be dangerous depending on the rooms they occupy. For example, leaks can cause shorts in wiring, resulting in serious electrical shocks. A leak can also weaken surrounding structural support increasing the risk of room collapse. When you find a leak, before trying to intervene, take a few moments to assess the situation and look for any possible safety hazards. 

Disconnect Power to the Affected Area 

You should immediately shut off the power to a room if the leak has either covered an electrical device, originates from an electrical device (such as an appliance), or has flooded to the point of covering electrical sockets. Proceed to your circuit breaker or fuse box and turn off the switches that control the flow of electricity to the flooded area. If you are unsure which circuit to switch, turn off all power through the main switch – this switch will disconnect power to your entire home and is found at the top of the box. 

Search for the Leak’s Source 

While some leaks can be obvious, such as a burst pipe or broken appliance, some can be deceptively difficult to identify. Many leaks originate from pipes you never see that run through walls and ceilings. In these cases, try to follow the trail of water to the source as safely as possible, and if the source is coming from inside a wall or ceiling, immediately proceed to shut off your home’s water main. 

Disconnect Water to the Leak 

If the leak is visible, you may be able to find a flow control valve. These are individual valves that allow appliances and specific pipes to access your house’s main water sources. These valves typically resemble small red wheels or small, silver, ovular wheels. 

Remove Standing Water 

Once the area is safe and the flow of water has ceased, you can proceed to remove the standing water. For small to medium-sized leaks, a wet vac is your best option, as it’s cheap, easy to use, and drains water quickly. You will need to use a pool pump or hire a professional for more significant leaks and full-on floods. 

Take Photos

Take photos of damaged structures, appliances, and furniture throughout the cleaning process. You will need these when you file your insurance claim. 

Inspect for Mold 

Alongside structural stability and electrical shocks, toxic mold is one of the leading health hazards associated with water damage. As you clean your home, keep an eye out for mold growth, and if spotted, immediately remove ventilation to the room before it spreads. Mold can be a severe problem, with certain species toxic to humans. You should always contact a professional if you notice serious mold growth. 

Ventilate and Dry the Area 

If no mold is immediately present, you should ventilate the area. Large box fans are adequate for small leaks and floods, but you need a dehumidifier for more significant or deep-set water damage. 

Remove Affected Porous Objects and Catalog Them 

As the area dries, you will want to remove all porous objects that have been saturated with water. Small objects like shirts, blankets, and stuffed animals are salvageable if washed quickly. However, anything that won’t fit into a washing machine must go. 

Clean Location to Prevent Mold Growth 

Once the area is dry and the waterlogged furniture has been removed, you will want to clean every surface that has been affected by the water. This cleaning will remove any immediate bacteria and kill the lingering mold spores spread by the water. Numerous antifungal soaps are explicitly designed for this situation, but a bleach solution works just as well in a pinch.

Call Your Insurance Company 

Dealing with water damage after a massive leak can be catastrophic, but you don’t have to go through it alone. Unfortunately, most homeowners insurance policies don’t cover floods and natural disasters, but occurrences like burst pipes or broken water mains are often covered. You should always contact your homeowners insurance company to help cover the repairs if you have encountered severe water damage. 

Call a Water Damage Restoration Company 

If the water damage has seeped into your home’s walls, ceiling, or floor, it may be too much for you to handle. If that’s the case, it may be time to call a water damage restoration company. These industry professionals can help get your house up and running after a flood or major leak. 

Final Thoughts

When faced with extreme water damage, it’s essential to keep a cool head. Always assess the situation for shorts in wiring, weakened structural systems, and other hazards before trying to resolve a leak. Then, once the situation is stable, you can use the information in this article to proceed with mitigating the total damage the leak has caused.

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