Okay, your sunroof drain or A/C evap drain clogged and made a mess. There are other posts here about fixing it and you got the drain open, the carpet seems to be drying out and things look okay. But are they?

Many Nissans have as much as 2" of foam spacers between the floorpan and the bottom of the carpet, and all Nissan carpets have a layer of impermeable plastic, either on the bottom or internally. If you didn't lift the carpet, there could be an inch or more of water underneath with no visible clue. Left long enough, I've literally found white pond-scum growing in floorpans. Worse, damp-but-not-wet conditions are ideal for growing stachybotris, and that will be the conditions on the bottom of your carpet if there's water in the pan that isn't high enough to soak the undercarpet. You don't want to fool with stachybotris, it's the black stuff that causes houses to be torn down. It poisons the central nervous system and can cause everything from memory loss to Parkinson-like tremors to full-blown early Alzheimers. Some of those are fates worse than "just" death, no joke! So wear an N95 when you first lift the carpet, and wear it for the whole job if you find any evidence of black mold.

So that's the first rule, pop the door sill trim at all 4 corners and lift the carpets. If there are only puddles and no odor of mildew then your carpet is probably safe. The source of the flood matters too, an evap overflow is basically distilled water and much less likely to provoke mold than rain runoff or river water. If there's little water and no smell, sop up the puddles and spray some bleachy Lysol (purple bottle) on the spacers and floorpan to disinfect it. Bleachy Lysol is your best friend after any flood, and get the name brand, not an imitation. The genuine stuff is color-fast to all Nissan interior fabrics (although watch out for your clothes), but some imitations aren't safe. However, one caveat, get a good utility spray bottle to apply it. The Lysol spray head is crappy and won't produce a good mist, it pretty much "spits" instead of misting.

If there's any mold smell or more than a few sponge-fulls of water, you're going to have to remove one or both front seats and lift the carpet for inspection. Very often only one side of the car will be involved, with the center "hump" preventing overflow to the other side of the pan. If that's the case, don't do more work than you need to, but check front and back. Most floorpans tilt slightly rearward and there can be little water in front but a half inch in the rear. So check it, don't assume. To get the carpet all the way up, in addition to pulling the seat, usually the lower B-pillar trim and the rear lower cushion will need to come out as well. You'll be looking for patches of visible mold, particularly any that are black in color. If you find none, or only a few patches of green or white stuff, then your carpet is salvageable. If you find widespread patches, or any amount of black mold, your carpet is toast, replace it.

If you find it salvageable, it's important to disinfect the undercarpet before you dry it out. Mold spores are most dangerous when the mother mold dries out, so you don't want to dry it first and potentially spread spores all over the car. Hold the loosened carpet up vertically with bungees on the steering wheel or center console and soak it thoroughly with bleachy Lysol while it's still wet, especially in any spots with visible mold. Also soak the base of the firewall padding anyplace it's wet, as far up as you can if the leak was from a windshield seal. Once that's all disinfected, remove the foam spacers from the floorpan and if necessary open the drain plugs in the bottom of the pan. The latter are usually a PITA because they're covered with body-sealer, so I generally put a hole in them with a 1/2" drill instead, then cover it back up with RTV before laying the carpet back down. Gravity will send the water in the undercarpet gradually dripping off the bottom edge, and a thick undercarpet can hold nearly half a gallon. So you may need to let it "drip off" for a long time before you close anything up. Once the dripping slows, putting folded pig mats or soft shop rags under the bottom edge will help "wick out" remaining water, and placing a shop fan and/or space heater in the car will greatly speed the drying process. After drying, spray the whole floorpan with a light mist of bleachy Lysol to disinfect it before laying the carpet back down.

The foam spacers should also be treated with bleachy Lysol on both sides, or left out in the sun for a few hours on each side (direct sunlight is instantly fatal to most forms of mold). Many of them come from the factory with protective plastic bags over them, and these usually fill with water. The spacers can be very expensive for a simple piece of blown foam, some as much as $150, so you won't want to discard and replace them unless they're far gone. If the coverings are filled, just tear them off and treat the underlying foam. You can then either re-use them without a covering or replace the cover with a trash bag. To be safe, you may want to give the seats the same sunshine treatment even if there isn't any smell.

If the carpet needs replacement, or if there's heavy mold smell throughout the car, you'll want to disinfect the whole car, upholstery and all. To do that, you'll need a common crockpot and a half gallon of floor cleaner. We use Lysol, but any disinfecting cleaner will do. If you prefer the smell of Pine Sol, that works fine. If the carpet is being replaced, do this step with the floorpan bare. If it's being saved, do it after you dry the undercarpet and lay it back down. Here's a pic of an Altima that recently got a Lysol-boil after two clogged sunroof drains trashed the carpet:

The seats were all placed back into the car and the rear seatbacks dropped to expose the trunk. The open crockpot was left on medium overnight with the doors and windows closed. The "fog" visible on the windows is actually Lysol vapor, and the humidity will hit you like walking into the Amazon jungle when you first reopen a door. The fumes penetrate every corner of the car and will leave it smelling pleasantly Lysol-ly for days, permanently killing any mold smell. It's very effective. We once had a brand new '16 Maxima with a window left open by a lot man, then closed up after it was rained on. It sat for nearly 2 months before the problem was discovered. By then the mold reek was unbearable, I wore an N95 just to get it from the parking lot to a service bay. We replaced the carpet and gave it a particularly long boil, 2 days and a full gallon of Lysol, but after that plus an ionizer treatment, it smelled like nothing but brand new leather. We got no complaints from a customer when it was sold a week later. I should add that insurance companies love us for this, we routinely save cars that would be doomed as auction junk in many other places. When we list a "Lysol boil" on a repair estimate, none of the local adjusters ask questions anymore. 'Nuff said!

Lastly, while Nissan/Infiniti products tend to have no electronics in the bottom of the floorpan, there are some exceptions. Many have the power seat grounds there. Some Sentras have the G-sensor in the bottom, and Quests with Bose have the amplifier in the closed bottom of the spare tire well. Gen2 Rogues have the Bose underneath the passenger seat, not in the pan but barely an inch above it. So while the carpet is up, make sure to clean any connections the water may have reached. For plug-in connectors, chase any water with WD40 and then apply di-grease before plugging back in. If the equipment lacks a sealed housing, such as an amplifier, yank it and give it a "rice treatment" to maximize the chances of saving it.

Hope this helps you, and no... don't trade in your Nissan for an ark. With some knowledge, patience, and elbow grease, even a whole lot of water doesn't need to be fatal. Happy motoring!

Awesome post!!!