Dear Dave,
Can I safely store water in my toy hauler water tank for a week? —Steve, 2026 Coachmen Adrenaline
Dear Steve,
I have left water in the fresh water tank for more than a week on trips without having it go bad, and I would imagine most of our readers have done the same thing. Your fresh water tank, for the most part, is a sealed system, unlike having the water open to the elements. However, there are a few variables that you should consider.
Treated city water
Water that comes from a city or municipal source and has been treated can safely sit for several weeks and remain stable. However, most water that is supplied by a campground or even some of the RV-friendly fueling stations is well water and not treated, so it can contain minerals and other components. It would be best to filter any water you might use in this case to get some of the calcium, lime, and rust out before storing it.
Tips for longer-lasting stored water
Start with a clean, sanitized tank. If you have been using well water previously and have let it sit for a period of time, sanitize the tank before filling it for the extended usage. You can use a solution of 1/4 cup bleach for every 20 gallons of water capacity. The bleach will kill the bacteria in the fresh water tank and the water heater.
However, keep in mind it will also kill good bacteria needed if it gets in the black water tank. Start with an empty black water holding tank and you may need to flush it a few times and start with a fresh treatment solution.
Sanitize the fresh water tank
Another option is to use the Thetford Fresh Water Tank Sanitizer. It uses a detergent and a chemically balanced sanitizer to remove 99% of harmful bacteria without leaving a bleach odor or soapy residue. You can find it on Amazon here.
Make sure you thoroughly clean your water heater reservoir, as calcium, lime, and rust will settle in the bottom. Since the drain plug is at least an inch above the bottom, it will not drain out without using a flush wand like this one available on Amazon. I like this model as it has a threaded connection. Several readers have commented that the cheaper version with the plastic wand has blown off with pressure and it’s hard to fish it out of the tank.
“Freshen” the drinking water
One last “ounce of prevention” would be to use the Camco Drinking Water Freshener that will prevent algae and slime build up. It will also get rid of odors and bad taste. One ounce treats 20 gallons and is very cost-efficient. You can get it on Amazon here.
You might also enjoy these posts from Dave
- I find most campground water is horrible. Can I travel with a full fresh water tank?
- Beware damaging your RV with high water pressure in campgrounds
- How do I sanitize my RV’s fresh water tank through the filter?
- Your RV’s fresh water system: What you should know
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Amazon or Camco don’t tell you this.
The active ingredient in Camco TastePURE Drinking Water Freshener is Sodium Hypochlorite (diluted bleach), which makes up just 0.2 – 0.4% of the liquid. The remainder of the solution is simply water. [1, 2, 3, 4]
Isn’t it ironic that one of the largest RV accessory companies sells the cheapest plastic flush wand?
You would think by now they would have improved it.
BTW, my trailer may sit in storage for 3-4 weeks. I always sanitize before use. The time it takes to do it, 1/2 to 1 hour, ensures the water is safe.
When Dave says to filter well water before going into the fresh water storage tank, I wholly agree – but when he mentions calcium, lime or rust, know that the common RV water filters remove only larger particles which rarely include any of those 3 items. You have to use more advanced filters (e.g. water softeners) to remove these dissolved minerals.
I sadly discovered the metal hot water tank rinser doesn’t fit the newer capped (not plugged) Dometic unit. I returned to the Camco wand after better securing and sealing the plastic tube to the valve.
You said the bleach would kill the bacteria in the fresh water tank and the water heater ( I assume this is the same as the hot water tank). I have read and been told never run the bleach through the hot water tank.