Thanks for the reply.
I'll check for leaves or clogged drainage channels.
The fender liner around the rear wheel is broken. I'll fix that straight away. Hopefully that is it.
I have not done any mods to the vehicle. I do not see anything that looks like a mod but this is my first 3 so dont really know what to look for.
The water looks like it has soap in it. I thought this might be from the dealer washing the carpets.
did you just purchase this car? if so even if the carfax/autocheck etc say there have been no accidents it is still a possibility that the car was in a minor accident and may have been fixed without the use of insurance, if this was the case then the car history checkers will usually not find this as most body shops will not report these incidents if insurance is not involved (less paperwork for them) so it IS possible your door has been removed or replaced at some point and is misaligned, again I find this unlikely but with buying used you never fully know what you have until you have it. I had an 06 sentra no reported wrecks nothing, car drove fine even a shop I had inspect the car did not see the issue it had, but on doing its first oil change I pulled the splash shield off and noticed the metal subframe part of the bumper (where the foam goes behind the plastic) had a huge triangular shaped dent in it like the car had been run into a poll or tree and the previous owner had just gotten a new bumper of matching color and slapped it on there (they obviously knew how to line it up as all the panel gaps where even front to back and side to side on the whole car, even with the subframe off slightly) that car drove fine and never gave me any issues surprisingly, even did a good job protecting me when my idiot self wrecked it yet again and totaled it (ive done that too much, getting better) so just a quick lesson on actually looking over a car 100% which means taking the shields off, using a flash light in crevices and getting dirty and also having a thorough inspection before purchase.
I turned away 1 mazda 3 I was inrested in after crawling under it and finding rust everywhere on the body the suspension components EVERYWHERE then I asked the owner where the car was from he said Pennsylvania I said sorry I am no longer interested and left after that as I live in Texas and I am not dealing with a car from up north with rust issues.
I turned down another at a mazda dealer (this one is kind of sad) it was supposedly certified preowned 2013 3 hatch I test drove it after giving it a cursory look over and noticed right away the steering was off to the right kinda bad, so I asked why they said just needed an alignment (which it may but read on) I also noticed very harsh vibrations and rough shifting (it was an auto) so we get back to the dealer and I continue looking it over, popped the hood first thing I see, the engine is tilted to the left (my perspective) and the passenger motor mount was completely broken (rubber part) and the engine was now sitting lopsided as the passenger mount had obviously been bad awhile and broke the other mounts down to that point. (this is not good as it strains anything connected to the driveline) so I knew where the vibration was coming from by then, the bad mounts. so im already not buying this car, I look at the tranny fluid since it was shifting so horrid, it was muddy black and watery and smelled burnt. the sales man asked if I wanted to run numbers at this point I said no, he then got his manager out there and I proceeded to show him everything wrong with a car they had listed for $12k that was worth maybe 8k if they where lucky bald tires, bad alignment, broken motor mounts, burnt up tranny fluid, the car needed at least $3k worth of work just to be in decent shape and that was if the bad mounts had not broken anything else. as it needed $500+ in tires $90 in alignment $300 worth of motor mounts (without labor on top) $120 transmission fluid exchange, if the bad fluid had not already ruined the transmission. I was willing to bet the mounts being bad had strained the cv axles and they where on their way out so add $300 for them (just in parts) and the inside was beat up as well as the paint not in great shape either. the manager said "this car has been certified by our mazda factory trained techs" I simply said back "your factory trained tech is obviously an idiot or asleep when they went over this stuff, because I guarantee you we get a tech out here and I show him this stuff he would agree this car is in bad shape" he then proceeded to tell me to leave as someone else was interested in the car and he did not want to deal with me, so I walked over to the other people looking at the car and showed them everything wrong with it, said mazdas are great cars but like any car have to be maintained, this one was not let me show you, and after i showed them they left right behind me.
The manager obviously wanted me out because I caught them and their "play" trying to pass off a POS as certified when it clearly had not even been looked at by a tech, as I know even the worst tech in their shop would have seen the tranny fluid was not right and the alignment was off, as well as the bald tires and lopsided engine, all I had to do was look at these things, nothing special and I could plainly see the car was in dire need of immediate major mechanical work to be road ready.
I ended up buying a 2011 3 (the one I have now, and pictured in the fuelly banner in my sig) from a bmw dealer in the metroplex. it has been great so far, few hiccups but nothing I did not expect or could not handle first thing the passenger headlight started leaking in the rain the dealer gave me a 60 day warranty with purchase so they warrantied that and got me a new assembly, ballast, ballast seal and bulb after speaking with the manager for only a minute or 2 about the issue (it happened 2 days after purchase) and that satisfied me just fine only other issue its even really had was the common (non skyactiv models) motor mount failure. mine was not as bad as the one I looked at above, but I could tell on the test drive the passenger one was beginning to fail (and would need a new one sooner rather than later)as it had some unexplained vibrations I had felt before in my 08 so I knew right away what it was. but I had a dealer change the passenger and driver rear mount (the passenger fails then that rear driver then the tranny ones, if left unfixed on the other 2) and it drives solidly now no vibration tighter steering and better braking response, plus no shift shock (automatic, the motor mounts affect that a lot more then most people realize) and the tires that where on it where LOUD firestones, that where still at 9/32nds tread life, but where so loud I had to rid myself of them, sounded like a wheel bearing was failing after about 1,000 miles of driving after purchase (alignment was slightly of before they got it, they aligned it but it had obviously messed up the tires , some new cooper rs3-a fixed that right up, quieter than a church mouse on sunday now. that and the minor complaints of no metadata on my display when using Bluetooth streaming on a phone that supports the avrcp 1.3 that the car needs to display that, but im not sure if its a car issue or a phone issue as I tried 2 samsungs a s4 and s7 and neither will display song info but my windows laptop will so that shows me the car does support it and it does work, so it maybe a phone thing.
and the other minor complaint of having to re turn on cruise every time I get in the car, my 08 the yellow cruise "ready" light would stay on (main cruise on function) after turning the car off (so upon driving all i would need to do is hit set and be good) until you disconnected the battery or turned it off with the off button, this 2011 I have to hit "on" then "set" every time I drive and I forget to hit "on" sometimes and have to hurry in traffic as I start losing speed when it doesn't engage again minor complaint. this is the only car I have ever seen/had that did this, my dads 2014 6 the cruise main on stays on and he just has to hit set when he wants to use cruise, my sisters old 07 6 did as well and so did my 08 3 and all the other cars from 96 sentras to 98 pathfinders etc I have owned. even our manual states it does not remain engaged when the ignition is off as it does not remember this (though it remembers tons of other ancillary crap like if I disconnect the battery my Bluetooth stays paired and it remembers radio presets after the battery is disconnected but it cant remember that cruise was on and leave it in the "on" or ready state unless I turn it off with the off button? lol rant over sorry to thread jack
yes also check for leaves and yes coolant is harmful to you, but many people don't realize there is Propylene glycol in breakfast cereals and other foods and this is also in your antifreeze, though it is supposedly non toxic, I would not chance drinking a bottle of antifreeze
check the cowl (plastic under wipers) for leaves stuck in the vents and check under your fender liners at there are drains there for the door and what not and these maybe clogged, in a car like this and as new as yours is I doubt its anything major like a failed heater core, though it is possible on any car of any age for them to fail, parts do that. Im willing to bet you have a ripped seal or clogged drain somewhere
sorry for the long ranty post, was in a rant mood, also sorry most of it seemed off topic, but I was trying to get across that you have to inspect a used car very well yourself and don't trust a dealer to do it, if you have a good shop take it there on the test drive and let them look at it for you, whether you know how to fix a car or not its always good to have an independent set of eyes look it over for you, as they don't care if you buy the car, but you may love it so you may have a bias and over look something big 
