Symptoms of Water in a Car’s Gas Tank and How to Fix it?

Whether it enters by accident or on purpose, water in the gas tank of an automobile is definitely a problem that needs to be addressed immediately. Water can enter your fuel tank either when you fill

What happens when you put water in a gas tank?

up the tank from the pump or from condensation within your fuel tank due to weather. Here are some of the symptoms that you may experience if there is water in your gas tank. We will also go through how you can fix this problem.


How You Know If Water Is in Your Gas Tank

One of the symptoms that you will immediately experience if there is water in your gas tank is trouble with acceleration an hesitation. If you have trouble getting up to highway speeds yet there is nothing wrong with the rest of your vehicle, you should look into the possibility of water in your tank.Issues accelerating? There may be water in your gas tank.

You may also experience volatile changes of speed that you do not implement while driving. This may also take the form of a sputter. If your gas tank is full and your car still sputters when you hit the accelerator pedal, then you may want to look into the possibility of water contaminated fuel.

How to Fix the Problem of Water in Your Gas Tank

The best way to remove all water from the gas tank is to simply replace the entire volume of gas that is being used. This may seem like an expensive alternative to some drivers; however, the damage that you will be avoiding to your car is more than worth it.

HEET® is a fuel additive that is made for removing water from the gas tank. However, if there is more water in the tank than there is gas, fuel additives will not work.

The best way to remove bad gas from the tank is a process of immediate displacement, siphoning out the old gas while immediately placing high octane gas in the tank as quickly as possible. Depending on the amount of water in the tank, you may want to drain the gas tank and leave it empty for a while so that it can dry out.

If you do not have the wherewithal to perform this procedure on your own, it is well worth the time to get a professional mechanic to take on the job. Water in a tank can cause thousands of dollars’ worth of damage to a vehicle if not dealt with properly.

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  • I had rust in a motorcycle tank. I used Apple Cider Vinegar to remove the rust and immediately rinsed with distilled water mixed with 3 tablespoons of Bakingsoda to neutilize the acid from the Vinegar. I did this twice and then rinsed several times with filtered water/final rinse with distilled water. I dried the tank best I could with hair dryer including heating seems of tank to help. I could not hear any water, yet sure some small amount must still in tank??? I then filled tank with non ethanol regular gas. I will not be starting bike for several months, and will drain tank again before attempt to start, but would have more piece of mind to get remaining water out now. Is Heet product you speak of the best or do you recommend something else?

    • Hi James,
      In this case, We’d recommend adding STA-BIL 360® Performance™ or STA-BIL 360® Marine™ to this fuel which will neutralize any water that may have remained in the tank and preventing rust and corrosion. Or, simply keep a bottle of ISO-HEET® Brand (the red bottle) ready. When you are ready to drain the fuel tank again, add some ISO-HEET® to remove this excess water. Please contact us at if you have any questions about this.Thank you.

  • I have a 04 Nissan Maxima. Had half of tank of bad gas( golden brown in color). Siphoned all the gas out and also replaced my fuel pump. Car cranks but won’t start. There is spark and the pump is pushing gas to the front what now? Also tried starting fluid. It does not work

    • Hello, since we are not able to assess your Nissan in person, we recommend taking it to your nearest professional mechanic to be looked at.

  • After filling with gas my van misses badly after the engine has warmed up. Have put additives in gas tank, injector cleaner, replaced fuel pump, filter, computer and spark plugs.

  • F150 2016…..hesitates pulling out and when down gearing to stop.
    2. Instrument Cluster dries out, turns off the gauges with lighting, camera, and radio….This is another cluster I purchased on eBay. When I remove the cluster, and pull out the main harness and replug, the radio, camera works fines…but when I replug back the IC, starts acting up, turning all types of symbols, lights, and goes out.
    Any recommendations..

  • I have maruti suzuki Zen(petrol), it has problem of black smoke and water particles in exhaust pipe

    • Hi Rakesh, since we are not able to assess it in person, we suggest taking it to a professional mechanic. Thank you.

  • A friend brought me 3 gallons of gas when I ran out. I put most in tank then used a funnel at the end to get the last out. At that time I noticed gas was a white milky color!! Water??

    • Hello,it sounds like there may be some contamination. Since we are not able to assess the vehicle in person we suggest having it looked at by a trusted professional mechanic.

  • I have a 2002 ford f150. When I put gas in my truck. About 20 minutes later it started to jerk when I stop at a red light. What should. I do

    • Hi Calvin. Since we are unable to assess your car in person, we suggest taking it to your trusted professional mechanic.

  • Hey, I’m having problems with my car, but I am too cheap to take it to a professional mechanic. So I figured I’d post in an internet forum about products that remove water from fuel. Makes sense right? Come on people. Really?

    • Hi Jared, if you would like to try one of our products then here is a rebate for you:
      Please contact us at if you have any questions about how any of our products can help your specific problem.

      • Jared was making fun of all the people asking you guys to diagnose their car over the internet. Really though, props to you guys for putting in the effort to respond to these people, even just to politely tell them that you can’t help them.

        I’m actually reading this article because I have an XJ6 (two gas tanks) that has been off the road 10 years and has gum and dirty dried up fuel inside. I’ve scraped the inside and rinsed it out and plan to try out HEET in both tanks to take care of any trapped moisture.

        Does HEET mobilize the water so it can be run through the fuel system or is it somehow converted into something combustible?

        Thanks guys

        • Hi Ian, we always try to help anyone who has a question the best that we can! Yes. HEET will break away water particles for easier combustion. However, we would highly recommend trying ISO-HEET as it is specifically designed for more efficient water removal. Please contact us at if you have any questions about this!

  • Hi, i recently had gas that rain water get to it before I did and put it in my Ford Focus (2011), but thankfully did NOT start my engine before I was able to be warned. I have read lots DIY’s to remedy this issue myself hoping that becuz of being a single mom and always short on cash that there would be an easy answer. BUT, there are just too many choices. Here also is the kicker. The gasoline was stored in 50 gal. drum with a small opening on top, about the size of a shot glass. Well, the 10 gallons that was split between me and a friend of mine and I got the 1st 5 gallons and he got the last half. However, he drove 1st and I still have not. I didn’t know if this would make a difference on who probably got the more water and who didn’t? Also, any recommendations for his poor Trecel would be thankful, or is it going to be a pretty penny because he drove and I didn’t? Thanks so much, from Sunny California only rainy once in a while)

    • In this case, it seems that there is a chance that they might’ve gotten a little more water than what would be considered “safe” (over 1oz per gallon would be considered too much). Because water is typically heavier than gas, it will drop to the bottom (phase separation). This means the bottom fuel would be the most affected. Of course, if the fuel is shaken or stirred, then all fuel would be contaminated. If the fuel was taken from the bottom (syphoned or drained), then the friend might have gotten the most water. In either case, I would rather recommend not using this fuel and if it must be used, use a water remover such as ISO-HEET and dilute with fresh fuel as much as possible. Please contact us at if you have any questions about this. Thank you.

  • My car has been sitting for about a year now due to being totaled. I was occasionally starting it to keep everything moving engine-wise, but stopped for a few months because I had to cannibalize the AC compressor; that belt also ran the water pump. Once I attained a belt that would allow me to run the car minus the compressor, it ran fine for a while during the next startup, but then died after about 10 minutes. The engine now still cranks and tries to start, but won’t run. Could this be water in the tank from condensation? I live in Phoenix where the temps wildly fluctuate through the winter months.

    • While this issue could be caused by water in the fuel, this seems like it could also be mechanical failure in nature, or due to bad fuel –depending on how old the fuel is. If after adding ISO-HEET and fresh fuel does not fix the issue, then the next best option could be consulting an automotive mechanic.

  • I owned a1992 corvette that i bought on ebay. From the very first day i had the car it would stall out after awile.the car starts up right away and idles good after driving for5 10 miles or so it sputters or hesitants then stalls out.took to chevy dealer.he showed me water at the bottom of tank.he put in treatment told me to drive it several hundred miles ive gone through maybe tank and half putting heep treatment in before gas.i still have this problem.sometimes its hard to restart it right away.what to do

    • Hi, Robert. It seems that you may have already done all that you could, based on the previously diagnosed water issue. However, before you take it in for further servicing, I would recommend driving until the tank gets to about 10% full, refill completely with high octane fuel, and then see how the vehicle behaves. Adding a fuel system cleaner may also help such as 104+ Octane Boost. If the problem persists, then perhaps the next best option is to have a mechanic look further into it. Please contact us at if you have any questions about this. Thank you.

  • I wasn’t sure if this is water or what it might be. But when filling my tank, the gas nozzle stops and won’t continue to pump continuously in a steady flow unless you hold the handle and pump at a low volume. Any idea what this might be? I can fill the tank, but it takes forever.

    • Hi Patri, since we are unable to assess your car in-person we would suggest taking it to a professional mechanic. Thank you.

  • I had just filled my gas tank with premium gas. I decided to get my car washed and when I drove out of the car was, I noticed that I had left the cap hanging and the flap open. I do not know how much water was able to get in my tank. I don’t know what to do. I drove my car home without a problem. Please help!!

    • Hi Gloria, If the vehicle has not had any performance issues such as rough idling/handling, hard starts or stalls, it can be safe to assume that it should be OK. However, for safety’s sake, I would recommend adding a bottle of ISO-HEET to remove any water that might be in there safely and clean the fuel system. Also, make sure that you get rid of most of the suspect fuel and start fresh again. Please contact us at if you have any questions about this. Thank you.

    • Same thing happened to me. After filling my car and as I was checking my receipt if car wash was included in it I forgot to close my gas tank. As I parked my car after the car wash to inspect it I noticed the cap was left hanging.
      My worry is it’s not only water but also the chemicals used in cleaning. I hope the ISO-HEET will do the trick.

  • Check engine light is on 2005 Nissan Altima. Code is P0181 (fuel temperature sensor). This what I found
    What are the symptoms of the P0181 code?

    The vehicle will not start if the fuel is frozen from extreme cold or there is water in the fuel

    The vehicle will not start or may lose power and stall if the fuel gets too hot and boils off

    Sensors could malfunction if excessive additives in the fuel cause erratic sensor readings and cause the fuel to boil off at lower temperatures

    The ECM sets code P0181 to memory and turns on the Check Engine Light

    So am not sure if there is water in the tank. I brought Heet but not aure if I ahould use it or rplace the fuel pump again

    • Hi Mera, since we are not able to assess your car in person, we would suggest taking it to a trusted professional mechanic.

  • why is my land cruiser spitting out fuel gas
    after a short drive

    • Hi and thank you for the question! In this particular situation, perhaps it would be helpful seeking a second opinion from a different professional technician. If you have any other questions please contact consumer support at

  • I drove thru a car wash after filling up and forgot to put the gas cap back on. Could I have gotten water in the tank and or very much? Do all I need is to add something like heet to take care of it?

    • Hello! Yes, we recommend the Iso-HEET® Water Remover & Premium Fuel Line Antifreeze + Injector Cleaner. This is specifically designed to help remove water from the fuel system. If you have any other questions please contact consumer support at

  • I have a 2012 carmry and it started sputter after I got some gas cheap. I use fuel cleaner and it help should keep using it and no it was not (heet) use other brand. it still sputter when I put foot on gas it sputters and then is stop and then it might do it again.

    • Hello! Thank you for the question. However, in this particular situation, perhaps it would be helpful seeking a second opinion from a different professional technician. If you have any other questions please contact consumer support at

  • Oh my goodness! Impressive article dude! Thank
    you, However I am experiencing problems with your RSS.
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