--- title: "How to Keep Water Fresh in Your RV Tank for as Long as Possible" url: "https://camperfaqs.com/how-long-to-keep-fresh-water-in-rv-tank" author: "Tory Jon" published: "2021-01-05T18:20:23-06:00" modified: "2026-07-21T09:57:03-05:00" --- # How to Keep Water Fresh in Your RV Tank for as Long as Possible RVs are designed to bring the comforts of home with you on the road, with one of the main comforts being fresh water at your disposal. However, some care and general know-how are needed to keep your water supply and the system that holds it fresh. So, let's learn how long you can keep fresh water in an RV tank, plus tips to keep it fresh for as long as possible\! ## How Does an RV Water Tank Work? ![RV plumbing system diagram](https://camperfaqs.com/wp-content/uploads/2022/01/page-rv-plumbing-system-diagram.png) RV plumbing system diagram First, let's quickly cover how a fresh water tank in an RV works. If you're already intimately familiar with your RVs water system, you can skip this section. The fresh water tank is essentially a fiberglass (or plastic) storage tank that sits in the underbelly of your RV. It holds your fresh water supply for drinking, cooking, cleaning, and so on. Once you flush a toilet or open a faucet, for example, a pump draws water from the tank, and the water flows through the pressure release valve and into the aforementioned toilet or sink. Two tanks dispose of the water on the other end - a grey and black tank. A grey water tank collects the water from the sink or the shower. The black water tank takes in the wastewater from a flushed toilet. Pretty simple, right? ## Why Can't I Store Water in an RV Forever? Getting clean water from a reliable source and sanitizing the tank does not mean it will stay fresh forever. Eventually, the water will become contaminated and will continue to degrade until it's no longer safe to use. **The main causes of water contamination are:** - Mold - Parasites - Bacteria And these water contaminants can potentially enter your fresh water supply in a multitude of ways. ### How Contaminants Enter Your Fresh Water System #### Filling Hose Your typical garden hose can have lead fittings and non-safe liners on the inside and typically aren't labeled as "safe for drinking." When you [fill your RV water tank with freshwater](https://camperfaqs.com/how-to-fill-rv-water-tank-with-freshwater), you must use a non-toxic hose designed for drinking water. And be sure to only use this hose for the sole purpose of filling your water tank. #### Poor Water Source When you're out on the road, you will find yourself filling up your fresh water tank with water from various sources - RV parks, gas stations, wells, etc. In other words, you may not always know whether the water is safe. Only fill your RV tank from a source identified as potable. An RV water filter can reduce sediment, unpleasant tastes, odors, and certain contaminants, depending on the filter. Most standard inline RV filters are not designed to remove bacteria, viruses or every harmful contaminant. #### Poor Winterization & De-Winterization If you didn't properly [winterize your camper](https://camperfaqs.com/how-to-winterize-a-camper-complete-guide), you might have left excess water and moisture in your tanks and water lines, which will be a breeding ground for mold and bacteria as it just sits there for months. And remember, [de-winterizing your camper](https://camperfaqs.com/how-to-de-winterize-a-camper-trailer) correctly is just as important for safe and clean water. #### Not Sanitizing The Water System One of the most important steps to ensure clean and fresh water is to sanitize the water system. Not properly cleaning your water tank and lines will create the perfect environment for contaminants to grow. So, whenever you take your RV out of storage or if you start to notice a foul smell or bad taste coming from your water, be sure to properly sanitize your water system. ## How Long to Keep Fresh Water in Your Tank Before Changing > As a conservative maintenance practice, consider draining and replacing water that has remained in your RV tank for about two weeks, especially if you use it for drinking or cooking. Water does not automatically become unsafe after two weeks, and its condition depends on the source, tank cleanliness, temperature and how the system has been used. However, there is a multitude of factors that can affect how long your water will stay fresh. For example, the source you got your water from, how clean your water tank was before filling it, if you filtered your water before filling your tank, and so on. How you use the water also matters. Be more cautious with water used for drinking, cooking or brushing your teeth. Water used only for flushing toilets or other non-consumption purposes may be kept longer, provided it has no unusual odor, color or signs of contamination. ## Signs That The Water Is No Longer Fresh There is no guaranteed amount of time that water will remain safe in an RV tank. Its condition depends on the original water source, tank sanitation, temperature and possible contamination during filling or use. However, if you're starting to question the freshness of your water supply, then be on the lookout for the following: - **Foul Odor or Taste**: Stop using the water for drinking or cooking if it develops an unusual odor or taste. Keep in mind that harmful microorganisms may be present even when the water looks, smells and tastes normal. - **Change In Water Color**: This change will usually appear as orange or brown tinges. When the water is no longer fresh, it's also possible to start clogging the water lines. - **Illness**: If you or other campers develop nausea, stomach cramps, diarrhea or similar symptoms and the RV water may be responsible, stop drinking it and switch to a known safe water source. Drain and sanitize the RV water system before using it again. Seek medical advice for severe or persistent symptoms. You can test the water, as well, for harmful disease-causing bacteria like E Coli and salmonella periodically to ensure it's safe for consumption. ## How to Keep Water Fresh in Your RV Tank To keep the water in your tank fresh for as long as possible, there are a few things you need to routinely do. Skipping any of these can cause bacteria and other contaminants to grow, so make them a part of your regular maintenance routine. ### Flush the Water System As a conservative maintenance practice, consider replacing water that has remained in the tank for about two weeks, especially when it is used for drinking or cooking. After that, it's a good idea to completely flush the water out of the tank and lines. You essentially want to get rid of the water before any bacteria or contaminants have a chance to grow. **This will help keep your next tank of water fresher longer by reducing the number of contaminants that could potentially start growing in your tank.** You can flush the tank easily by running the water in the shower or putting a secondary hose in the toilet. At the same time, you should also [clean out the black and gray tanks](https://camperfaqs.com/how-to-clean-out-rv-black-water-tank). You can do that at an [RV waste dump station](https://camperfaqs.com/rv-dump-stations) and get clean water for your tank. Check out our post on [where to fill an RV fresh water tank](https://camperfaqs.com/where-to-fill-rv-fresh-water-tank) if your dump station does not offer fresh water. ### Sanitize the Tank Flushing the tank and replacing the water regularly will help, but you should sanitize the system for optimal cleanliness when taking your RV out of storage (or notice a foul odor). If you don't maintain it regularly, the smallest bacterium can grow and multiply. We cover this process extensively in our guide on [how to sanitize an RV freshwater tank and lines](https://camperfaqs.com/how-to-sanitize-rv-freshwater-tank-lines), so check it out. It also has some very important tips on what NOT to do when sanitizing your tank. To quickly summarize the process, the easiest way to sanitize your tank is with household bleach and water. Mix the bleach into the tank using a ratio of a quarter cup of bleach for every 15 gallons of water. **Important**: Do not pour bleach directly into the empty water tank. Mix the bleach with water first, dump it into the tank, then fill it the rest of the way full with water. Next, turn on the faucets until you smell bleach coming out of them, then close them. This fills the water lines with the bleach and water mixture. Now, let the mixture sit in the tank and lines for 12 hours to effectively sanitize it. Finally, [drain the fresh water system](https://camperfaqs.com/how-to-drain-rv-fresh-water-tank) and refill it with potable water. You may have to flush the system a few times to ensure the bleach is completely gone. Here's a quick video on properly sanitizing your fresh water system. [Watch this video on YouTube](https://www.youtube.com/watch?v=E0CsGjobAL0) If you don't like the idea of using bleach or find that bleach isn't working very well, use Camco's TastePURE Spring Fresh Water System Cleaner and Deodorizer. ### Use the Correct Hose Using your typical garden hose to fill your fresh water tank is NOT considered "best practice" since it may have lead fittings, non-safe liners on the inside, and typically aren't labeled as "safe for drinking." Even if your source supplies fresh water, the garden hose could potentially contaminate the tank. Instead, you should use a dedicated filler hose designed for RV use. Manufacturers designed these to fit tightly into the valve, lowering the risk of the hose carrying contaminants into your tank. Plus, they don't use any lead in the construction and have a chemical-free lining. ### Use an Appropriate Water Filter An inline RV water filter can reduce sediment, unpleasant tastes, odors and certain chemicals, depending on the filter’s certifications. However, most common carbon-based RV filters are not designed to remove bacteria, viruses or every harmful contaminant. Always fill your tank from a source identified as potable. If bacterial removal is needed, use a treatment system specifically rated for that purpose, such as a filter with an absolute pore size of 0.3 micron or smaller, ultrafiltration or reverse osmosis. Check the product’s certification and contaminant-reduction claims rather than relying only on the word “filter.”