We have Carpet Cleaning training, and over 10 years real world experience cleaning carpets, drying flooded carpets and removing smells from carpets in all sorts of situations - residential, commercial, thick pad, thin pad, no pad, berber, cut pile, area rugs,etc.

First of all, here's some basic information you should know that applies to all the answer below.

Residential carpet usually has a pad underneath it. The pad can be anywhere from 1/4 inch to almost an inch thick. The pad provides cushioning and gives your carpet that comfortable, soft feel when you walk on it.

Commercial carpet in offices and stores generally doesn't have pad underneath it.

Carpet pad absorbs water like a sponge: The problem with pad under a carpet is that it is a sponge and can hold many times it's own weight in water.

Pad is designed to cushion your feet, so it is spongy by nature and will soak up water like the cleaning sponge in your kitchen sink.

Carpet doesn't stop or hold much water:

Although your carpet may feel very solid under your feet, it offers very little resistance to water passing through it.

Carpet is actually like a sieve to water. A typical carpet will not hold more than a few ounces of water per square foot of carpet before it is saturated. After these initial few ounces of water have entered the carpet, any further water filters straight through the carpet and into the pad.

Carpet is like a sieve to water

Water likes to travel:Water doesn't stay put. It travels. The rule to remember is "Wet goes to Dry". Water will automatically move towards a dry building material.

Water at the center of a room will flow through the carpet and across the pad to the walls. It will migrate to the edges of the room in a matter of minutes or hours depending on how much water was spilled.

When you touch the carpet at the edge of the room, it may not even feel damp, but the pad could be saturated. This can be seen using an infrared camera. An infrared (or Thermal Imaging) camera is useful in finding the real area that the water has damaged, even if you can't see or feel it.

Below is a floor layout showing a flood cleanup job. The red circle is the source of the water - a broken toilet supply line.

The blue areas are the areas with carpet that felt wet and the home owner was worried about and wanted us to dry.

The orange areas are the areas that were actually wet as shown by the infrared camera and moisture meter.

The top 'actual wet' area is tile and cabinets. Although there was no visible water on the tiles, it had soaked through the grout and was under the tiles. The cabinet was also wet. The lower 'actual wet' area is carpet and and was found by the infrared camera and confirmed with a moisture meter. You can't see it clearly in the picture, but water had actually gone through the walls into adjoining rooms.

The picture below shows what a normal camera sees on the right The carpet looks and feels dry. But it's not dry, it is wet.

The infrared image on the left shows the pad underneath the carpet is wet. The darker the area is, the wetter it is. You can see how the water has traveled under the carpet along the wall. This is in the hall, 2 rooms away from where the source of the water was.

Bearing the information above in mind, here are some common myths about wet carpets and how to dry wet carpets

This is actually true, just like it is true that you could win the lottery with one ticket.

Yes, the carpet will eventually dry by itself. However, will it smell bad or have mold on it by the time it is dry? What other damage will occur while the carpet dries by itself?

Unless you live in someplace like Arizona or the desert where you have high temperature and low humidity, there is VERY little chance that the carpet and pad will dry before mold starts growing or bacteria start creating that wet carpet, damp smell. Typically you have about 72 hours to dry wet building materials before they start growing mold.

Even if the carpet itself dries, does that mean the pad is dry? There is very little chance that the pad is dry. The pad holds more moisture than carpet and is prevented from easily releasing the moisture due to the carpet above it and the sub-floor below it. So even if your carpet is dry, the pad is probably not dry.

Which brings us to another point. What about the wet sub-floor? Remember that carpet is like a sieve, and the carpet will pass water down to the pad very quickly. A saturated pad can then release water into the sub-floor.

Sub-floors are usually either wood or concrete.

Concrete subfloors are sponges too, except they are very slow sponges. They absorb water surprisingly quickly, but release it very slowly. So even if the carpet and pad are dried quickly, the concrete sub-floor could still release moisture for weeks.

Wood sub-floors hold water too. If they're made of chip-board/particle board/press-board (small chips of wood held together with glue) and they are wet for more than a few hours they absorb water, expand, and lose their structural integrity.

When wet particle board dries it has almost no strength and you will find yourself stepping through your floor if you're not careful.

On the right is a picture of wet particle board from a bathroom cabinet (I didn't have a picture of particle board sub-floor, as it's not very common). You can see how the board has disintegrated.

Plywood or OSB (Oriented Strand Board) are much more hardy choices for a sub-floor than particle board. If they get wet, you can dry them, as long as they haven't been sitting wet for long enough to warp. This falls loosely under the 72 hour rule. Another concern is dry rot which is a bacterial deterioration that takes 21 days to manifest at lower moisture levels.

Determining whether the sub-floor is wet or not can only reliably be done with a penetrating moisture meter as shown in the picture. Different building materials have different acceptable levels of moisture, so you use the meter to tell you if the material is acceptably dry or not.

Depending on the region you live in, plywood is dry at around 20% Equivalent Moisture Content (EMC).The picture shows perfectly dry looking and dry to the touch plywood.

However, when the pins of the penetrating moisture meter are inserted, you can see that the plywood is at 57% EMC, i.e. very wet. In as little as 4 days, mold can start growing on this wood if not dried correctly.

So, we know that the carpet and pad are unlikely to dry quickly enough by themselves. But even if they did, is that all you have to concern yourself with when your carpets are wet? No, it's not.

Like I said, WET goes to DRY. What this means is the water keeps spreading outwards from the source. The picture below explains it. This is the same house that is shown in the diagram at the top of this page. The pictures below are the area at the top right corner of the big blue "Feels Wet" area in the diagram at the top of the page. This is the door from the bedroom to the bathroom.

The carpet first got wet about 12 hours ago. During that time, the home owner used her wet vac to suck up as much water as possible from the wet carpet - about 100 gallons.

However, if you look at the infrared view of that area (the black and white picture on the left) you will see that even though the water has been sucked out of the carpet and has only been there for 12 hours, the water has wicked up the wall about 6 inches.

Wet drywall, what's the problem?

The problem is the usual 72 hour problem.

In as little as 72 hours mold can start growing on that wet dry wall. Mold especially likes dark, warm places with no airflow. That describes the wall cavity - the perfect place for mold to grow.

So that's the problem - wet carpet creates wet drywall which can create mold. Below is a picture of a wall after water had been standing for a long time.

To summarize. Yes, the carpet will eventually dry by itself. But you'll more than likely have mold and smells by the time it is dry, and then you'll be ripping walls and carpet out to fix the problem.

There is a myth that you can't remove water from a wet pad, even with commercial extraction equipment. People who say this are talking about the standard carpet cleaning 'wand' shown on the right. It is what is commonly used to clean carpets. It sprays hot water onto the carpet and then sucks it back up again.

The wand is designed to pull water out of the carpet fibers, not the pad and it does a good job at that. So if you have water damage on commercial carpet without a pad, the wand is a good tool to use.

However, on residential carpet with a pad, it extracts almost none of the water from the pad.

So how do you get water out of the pad so you don't have to remove and discard the pad?

There are a number of new commercial extraction tools that will remove water from the pad. Our favorite is the FlashXtractor shown on the right. It is a wonderful piece of equipment.

Below the FlashXtractor image is a picture of the water being extracted from the carpet that had been wet vac'd to death - still plenty of water in there!

Before tools like the FlashXtractor came out, there was a technique called "floating the carpet" which was used to dry carpet and pad due to the poor job the wand did of extracting water from the pad.

To float a carpet, you pull up a corner of the carpet and stick an air mover or carpet fan under the carpet to blow air under the carpet and onto the pad. While this method still works it is slower, less effective, and often stretches the carpet so that it doesn't fit properly when restretched.

Floating the carpet is an old school technique that is unnecessary if you have the right tools, ie a deep extraction tool such as the FlashXtractor.

To complicate matters, bear this in mind. While you can dry wet pad, it doesn't always mean you should.

If you have contaminated water in the pad you can dry it, but you will be leaving at least some contamination in the pad and over time, it will start to stink and rot. In contaminated water situations you will have to remove the pad because you can't effectively decontaminate it while it is underneath the carpet. In the water restoration industry, contaminated water is called Category 2 (gray water) or Category 3 (black water).

The truth to this myth is the same as for the question above. Basically, you can dry a wet pad, even without floating that carpet, but that doesn't mean you always should. See the answer above for details.

The answer to this question is in the answer to question 2 above. To summarize, you don't have to float carpet if you have a deep extraction tool and know how to use it.

Sometimes.

If you have a black water situation (Category 3 water - contaminated water such as sewage, toilet leak or rising ground water), according to the industry standard IICRC S500, you have to discard the carpet. I believe this is because there is no EPA registered disinfectant for carpet.

However, if you have Category 2 water (gray water such as washing machine waste water, shower runoff,etc) you have to discard the pad, but you can clean the carpet and keep it.

Category 1 water (clean water - toilet supply line, fridge ice maker, etc), and it hasn't been sitting for more than 48 hours, then you can extract the water and keep the carpet and pad.

The other reason water damage restoration technicians sometimes believe they should discard wet carpet is because the backing of the carpet will delaminate when it is dried. The backing is the lattice webbing on the back of the carpet that holds the carpet fibers together. It is glued on. If it gets wet and stays wet for a long time it can separate from the carpet fibers and start to disintegrate. How long is a long time? It's hard to predict - depends on the carpet, the temperature, how wet it was, etc. Normally by the time the carpet delaminates you've got a black water situation anyway, so the carpet has to go.

No. Not unless they use a deep extraction tool that is designed specifically to remove water from the pad. A regular carpet cleaning wand will not remove significant water from the carpet pad.

Yes, with a 'mostly' attached to it. The carpet cleaning machines and methods available to most home owners aren't very effective. Compared to commercial carpet cleaning equipment, the carpet cleaning machines you rent from the local supermarket are like a moped is to a Harley. They're the same thing, but not really.

Getting anything other than a light smell out of a carpet requires the high pressure and suction of a commercial machine. It also requires the expertise of a trained and experienced carpet cleaner. There are many causes and solutions to different smells in a carpet and knowing what to do and when to do it requires training and experience.

If baking soda and vacuuming don't work, your best bet is to call a trained and experienced carpet cleaner, preferably one that is also an IICRC certified Odor Control Technician.

Depends. If a carpet is dried quickly and properly there will be no smell. In fact, if anything, there will be less smell because the carpet has effectively been cleaned.

If the carpet and pad are not dried quickly and properly you will probably have a problem with lingering musky smells and mold.

Myth #9. You have to use a truck mount carpet extractor to dry or clean a carpet properly

False. This is an ongoing debate that I don't think will ever be resolved completely. Portable carpet cleaning machines have the advantage of short hose runs while truck mounts have the advantage of high power.

What it comes down to is really the technician holding the wand. A good technician on a bad machine will get a better result than a bad technician on a good machine.