Thursday, February 2, 2023


How long can you safely keep fresh water in your RV’s tank?

Having your RV sitting in the driveway, “ready to roll” on a spur-of-the-moment trip, is one of the gifts of our lifestyle. One thing you need to consider is how long does the “fresh” water in the RV’s tank stay fresh?

Got propane and gas in the tanks? Holding tanks empty? If you keep a few clothes in the rig, some non-perishable food items, and grab whatever else from your house fridge, your RV is up to an “instant getaway.” Ah, but what about the fresh water tank? How long can you safely keep water in it before worrying about “bugs”?

Our “germ free” society seems to be bent on scaring us to death. If you believe the TV commercials, if you don’t wash with “antibacterial soap” you’re sure enough going to drop over dead. It’s no wonder that many RVers (not just new ones) worry about how long it’s safe to keep water on board. Some even think they should drain their water heater between outings.

We checked with Uncle Sam’s water storage safety experts on the subject of storing “home prepared” drinking water, and here’s the thinking of the Federal Emergency Management Agency (FEMA).

Quality of the water source

Much depends on the quality of your water source. If you’re filling up your RV tanks with water from a “known” good source (a municipal water supply, as an example), then stop worrying about the water. Before you fill, make sure your tanks are properly sanitized. Not sure how? Check out our post on this subject.

Using a drinking water-safe hose, fill your tank from your safe water supply. Make sure the tank is securely capped to keep out unwelcome pests and road dust. Now settle back and relax. According to FEMA, “Replace the water every six months” is all that’s required. What about water in your water heater tank? Remember, when you fire up the heater, a lot of bugs are likely to be cooked to death. And if the water supply you originally filled up with is good, then the same “six month” recommendation applies.

If you’re really worried about water quality, FEMA suggests you purchase commercially produced drinking water, and keep it closed until you need it. It should be good until the “use by” expiration date printed on the bottle. Or you could use a water filter or purifier system (see below).

Ask Dave: What is the best water purifier? Dave discusses different water purifiers and filtration systems.



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1 month ago

Nice to hear common sense. I sanitize my fresh water tank and use the water out of it and have done that for decades with no problems whatsoever.

1 month ago

We buy bulk filtered water at commercial dispensers and reuse our plastic 1 gallon bottles for cooking or drinking. Tank water only gets used for washing. Have never had a problem with tank water IN THE TRAILER. Have had algae grow in the auxiliary tank I have in the bed of the truck when filled with campground water and left in the sun. That was a mess to clean up. I protect that tank from the sun now, and never refill from THAT campground. 🤣

Big Bill
1 month ago

Well we are part timers. This means our MH is parked for extended time when not in use. We seldom dry camp so we don’t have to rely on our tanks for perfectly clean water. We do drain and partially refill frequently. We do like to keep bottled water in the fridge especially when on the road. Everytime we dump the gray and black tanks we also drain and refresh the fresh water tank. 30 years of travel all over this great country and never an issue over water. We do carry a couple of gallon size water jugs from the grocery store for back up if needed. Simple low cost system that is very safe.

Mark W
1 month ago

Try using Purogene in your freshwater tank… works……

Yes, municipal water source is good and flush and circulate your water periodically.

We normally drink bottled water on our rig, tastes better.

32oz Purogene® Drinking Water Treatment and Water System Sanitizer for Water, Sanitizes Water Storage Systems, Provides for Long-Term Storage of Drinking Water

1 month ago

FEMA’s advice seems reasonable.

We drink, cook, wash, and shower with the water from our RV’s fresh water tank. At times, the water may be in there for a few months. The only time the tank is empty is during extended storage in sub-freezing conditions.
We sanitize with bleach before extended travels, several times per year.
Granted, we use a filtered water pitcher for refilling our water bottles.
To my knowledge, over the years, we have never run into any problems with our tank’s fresh water.

Wallace Wood
1 month ago

If you’re worried about what may be living in your fresh water tank, buy a dpd residual chlorine test kit. Run the water in the RV for 5 minutes and take a sample. Use the test kit. if the water or the test strip, depending on the kit, turns pink you have residual chlorine in the water. Nothing will grow. The chlorine will kill it. If it doesn’t change color, no residual chlorine and yes your water may not be safe to drink.

Thomas D
1 month ago
Reply to  Wallace Wood

We live on a well system. Hence, no chlorine. and no municipal water within 15 miles and they re on a BIG well. will they have chlorinated water. I doubt it. I think people worry too much

1 month ago

My water well is a “known good source of water” but it is not chlorinated and I would not trust it for longer than a month or so.

Robin Deane
1 month ago

As far as drinking water goes, I cannot justify the plastic waste that comes with bottled water (for me personally, not making judgments on anybody else–so don’t flame me). If you want to avoid the environmental damage plastic does, the best thing you can do is use a water purification system for drinking water and for cooking. The overall cost is less and you are doing the environment a favor.

1 month ago
Reply to  Robin Deane

Bingo! Same as me, and if anyone is really concerned about the environment they would stop using plastic water bottles for everything but emergencies! Judge if you like.

1 month ago
Reply to  Robin Deane

We camp once a month year around , drain tank Everytime especially in winter or pipes would freeze. Drink bottled purified water from the house and use the same plastic bottles over and over for years then recycle them. Fill tank with outside hose bib so same water we drink just not run through the Our pitcher.

Charles Allen
1 month ago

We live in Southern California (earthquake country). We use our fresh water tank mainly for dishes and flushing unless dry camping when we will fill with fresh water and use for drinking.With that said, when storing our rig in the winter we fill the fresh tank to the max and
have water available in case of an emergency. We have been through three substantial earthquake events in our lives and one of the biggest threats to life is no water.

1 month ago

We use only bottled water for both human and pet use. Fresh water tank, if used, is for flushing and, maybe, showers.

1 month ago
Reply to  tom

That’s just plain silly.

Charlie Sullivan
1 month ago
Reply to  Crowman

Why is that silly? We do the same thing, even at home. Although at home we use a Brita water filer to filter our municipal water for drinking and cooking…it just tastes better. And yes, we do recycle the plastic water bottles when using.

Gary Bate
1 month ago

I’m with you Charlie, we do the same. Who’d wanna drink gross unfiltered water out of a possibly stagnant plastic holding tank filled with questionable municipal water sources while on the road ?

1 month ago
Reply to  Gary Bate

See: First line of 3rd paragraph. Americans spend so much money, and waste so many resources, on making us “feel good”. We have used our Fresh tank in our current trailer for 5 seasons, with the only sanitizing done when we first purchased it. We use City water, unless we are at a campground that uses well water. Then we will use filters while we fill the Fresh tank, or inline with out City inlet connection.

1 month ago

The “recycling” you talk about still ends up with hundreds of millions of water bottles ending up in third world countries where they are generally not recycled. Often mountains of plastic are simply burned like garbage. You may feel good, but we are only exporting our problems on others. This is not an opinion, rather fact.

Last edited 1 month ago by Leonard
Dennis Johnson
1 month ago
Reply to  Crowman

Not at all. We do that also. Not worried so much about bacteria as we are adverse diarrhea bouts from minerals we are not accustomed to with our home (city) water.

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