How long does it take for mold to grow after water damage?

Mold spores are present in virtually every indoor environment and only need moisture, a food source (drywall paper, wood, carpet backing), and time. Under warm conditions, visible mold growth can begin within 24 to 48 hours of a water event. Cooler temperatures slow that window somewhat, but Chicago basements and interior walls rarely stay cold enough to stop microbial growth entirely. Starting the drying process within the first day is the most reliable way to stay ahead of it.

Does homeowner's insurance cover water damage from a burst pipe?

Most standard homeowner's policies cover sudden and accidental water damage, a pipe that bursts, a washing machine supply line that fails, a water heater that ruptures. They typically exclude damage from gradual leaks (a slow drip under a sink that went unnoticed for months) and almost always exclude flooding from outside the home unless you carry a separate flood insurance policy through the NFIP or a private carrier. Read your declarations page carefully and call your carrier as soon as possible, delays in reporting can complicate claims.

Can I stay in my home while water damage restoration is happening?

It depends on which rooms are affected and what type of water caused the damage. For a contained clean-water loss in one room, most people can remain in the home while drying equipment runs. If the damage involves sewer water, significant mold growth, or has affected HVAC systems, staying in the home is not advisable until remediation is complete. Your restoration company can give you a specific assessment once they've inspected the affected areas.

What's the difference between water mitigation and water damage restoration?

Mitigation refers to the emergency phase, stopping further damage, extracting standing water, and drying the structure. Restoration refers to the repair and rebuild phase that follows: replacing drywall, reinstalling flooring, repainting, and returning the space to its pre-loss condition. Some companies handle both under one contract; others hand off between phases. When you're getting estimates, ask explicitly which scope each contractor is pricing so you're comparing the same work.

What To Do in the First 24 Hours After Water Damage

If water is actively coming in, from a burst pipe, an overflowing appliance, or a roof leak during a storm, stop the source first. Shut off the main water valve, unplug appliances near the water, and get everyone out of any room where the ceiling is sagging or outlets are submerged. Once the immediate danger is controlled, the clock starts. Mold can begin colonizing wet building materials within 24 to 48 hours, and the decisions you make in the first few hours will determine how much of your flooring, drywall, and framing survives.

Step One: Stop the Water and Cut the Power

The main water shutoff for most Chicago homes is in the basement, typically near the front foundation wall where the service line enters from the street. If you’ve never located it, do it now, before you need it. Turn it clockwise until it stops.

Once the water is off, go to your electrical panel and shut off the breakers for any room that’s wet. Water and live circuits are a lethal combination, and standing water can carry current even if the source looks far from an outlet. If you’re unsure whether the panel itself is in a wet area, don’t touch it, call an electrician or your utility provider first.

If the flooding is coming from outside, a backed-up sewer, a sump pump failure during one of Chicago’s heavy spring storms, do not wade through it. Sewer water is a Category 3 biohazard. It contains bacteria and pathogens that make ordinary flood water look clean by comparison.

Step Two: Document Everything Before You Touch It

Before you move a single piece of furniture or pull up a single rug, take photos and video of every affected room. Walk the perimeter. Open closet doors. Lift the edge of any area rug and photograph the subfloor underneath.

This documentation is the foundation of your insurance claim. Adjusters work from evidence, and evidence disappears the moment cleanup begins. Capture:

The water source or entry point
The waterline on walls (use a pen to mark the height if it’s receding)
Every item of furniture, flooring, or personal property that’s wet or visibly damaged
Any building materials, drywall, baseboards, cabinetry, showing saturation or staining

Then call your insurance carrier and open a claim. Most homeowner policies cover sudden and accidental water damage (a burst pipe, a washing machine failure) but exclude gradual leaks and flooding from outside unless you carry separate flood insurance. The sooner the claim is open, the sooner an adjuster is assigned.

Step Three: Remove Standing Water and Begin Drying, Carefully

If there’s less than an inch of standing water and you’re confident it’s clean (Category 1, from a supply line or tap), you can begin removing it yourself with a wet/dry vacuum or mop while you wait for professional help. Every gallon you remove is one less gallon soaking into your subfloor.

What you should also do:

Open windows and interior doors to increase airflow, if outdoor humidity is lower than indoor (in summer, this may not help, Chicago’s July air can be as humid as the room itself)
Run any dehumidifiers you have on their highest setting
Pull soaked area rugs outside to dry or discard them, rugs trap moisture against hardwood and accelerate warping
Move furniture off wet carpet; place aluminum foil or wood blocks under legs to prevent rust and tannin stains

What you should NOT do:

Run a standard box fan directly over wet carpet laid over a wet subfloor. It dries the surface while the moisture underneath stays trapped, and that’s where mold grows.
Use your home’s HVAC system as a drying tool if the ducts may have been exposed to water. You risk spreading contamination through the whole house.
Assume that because the surface feels dry, the material is dry. Drywall can feel dry to the touch while the paper backing and the wood stud behind it are still saturated. A moisture meter tells the real story.

What NOT to Do (and Why It Matters)

A few mistakes made in the first 24 hours routinely turn a manageable claim into a gut-renovation:

Don’t delay on wet drywall. Drywall is essentially compressed paper and gypsum. Once it’s saturated, it loses structural integrity and becomes a food source for mold. If a section has been wet for more than a day, it almost always needs to come out, but the framing behind it may be salvageable if it dries quickly. Waiting a week to make that call usually means the framing goes too.

Don’t ignore the smell. A musty or earthy odor in a room that flooded, even after it looks dry, is an early indicator of microbial growth. That smell doesn’t come from the water itself; it comes from mold metabolizing organic material. If you’re smelling it, the problem is already underway.

Don’t throw away damaged items before the adjuster sees them. Exceptions exist for health hazards (soaked mattresses, contaminated food), but document everything before disposal. A photo on your phone is better than nothing.

Don’t skip the subfloor check. In Chicago’s older housing stock, the two-flats and bungalows built between the 1910s and 1950s, hardwood floors are often laid directly over board subfloors with no vapor barrier. Water migrates fast through the seams. If your hardwood is cupping (edges higher than the center) or buckling, the subfloor beneath it is almost certainly wet too.

When to Call a Professional Restoration Company

Some water damage genuinely is a DIY situation, a small supply-line drip caught in an hour, a single room with clean water and no subfloor penetration. But call a professional restoration company when:

The water source is a sewer backup, toilet overflow, or outdoor flooding (any gray or black water)
The affected area is larger than roughly 10 square feet of flooring or drywall
You can see or smell mold, or the water sat for more than 24 hours before cleanup began
The water reached electrical panels, HVAC equipment, or insulation inside walls
Your insurance carrier is involved and you need documentation of drying progress

Professional water damage restoration uses calibrated drying equipment, industrial air movers and desiccant or refrigerant dehumidifiers, that operate at a different scale than anything available at a hardware store. Drying is also tracked with moisture meters and thermal imaging cameras that find pockets of saturation behind walls and under floors before they become mold colonies.

The Longer Recovery: What Comes After the First Day

Professional drying typically takes three to five days, depending on the materials affected and how quickly the process started. During that time, equipment runs continuously and readings are logged to meet the IICRC S500 standard for water damage restoration, documentation your insurance carrier will expect.

After structural drying is complete, any materials that couldn’t be saved (sections of drywall, damaged insulation, warped flooring) are removed and replaced during the reconstruction phase. This is also when mold testing may be recommended if there was any delay between the water event and the start of drying.

The full timeline from water event to finished repairs can range from a week for a simple clean-water loss to several months for a major flood with structural damage. The variable that most consistently shortens that timeline is how quickly the first 24 hours went.

If you’re in the middle of a water loss right now and the situation is beyond what you can manage alone, Dry Bros Water & Fire Restoration serves the Chicago area and can be reached at (877) 379-2767. The right call at the right time is the single biggest factor in how much of your home, and your claim, you get back.