Sanitizing Fresh Water Tank (Avalanche 390DS)

[The Other Aaron]

Hey everyone, new guy to RVing here. I'm trying to figure out how to manually fill the fresh water tank with the diluted bleach solution the owners manual suggests, but it's not clear *where* to put it. There's the usual water inlet in the side panel, but then there's another unlabeled water hose inlet (top right in pictures). Is that the right one? If not, what is it for? Also, if not, I think I read somewhere in the forum here to use the fresh water tank vent, which I think is located between the kitchen and aft bedroom slide-outs. Is that correct? (Looks like a black plastic elongated semi-circle, with a barely visible embossed "vent".



We're full timing in an RV park to start. We have fresh water hookup, which has been great, but the park just had a water outage and we had no water in the fresh water tank, so we just used inexpensive bottled water for everything from washing to flushing (showers had to wait).


We're learning a lot for sure. In fact I'll be posting another question here shortly (electrical related). Thanks in advance for all your help. This seems like a good, friendly, helpful forum.

[jxnbbl]

I do it the simple way. When starting to fill the tank, I pour the bleach into the hose just after my inline filter. Reconnect to the filter and turn on the water.

[jxnbbl]

Sorry just noticed that you additionally want to know what to connect the hose to...im not familiar with this setup if you post the model trailer I'm sure someone could help. (and update your profile would make that "sticky information" for reference to future posts.

[flybouy]

To fill the fresh water tank turn the water supply off. Turn the handle beside the hose connection to "fill" and turn on the water supply.. Easiest way to add bleach is to put it in the hose as suggested. After running the bleach solution. After running all faucets, including outside shower, let the solution set for a few hrs. After that you'll need to flush the system with fresh water until no bleach can be detected.

BTW, in your Pic the gray water drain handle is open. Do not leave any drain valves open after draining. Doing so can lead to insects and odors entering the camper as well as solids settling in the tanks and pipes causing issues.

[dutchmensport]

How to add a sanitizing solution to the fresh water tank 101!

Follow these instructions if your camper is equipped this way.

The recommended solution of bleach to water is 1/4 cup bleach for about every 15 gallons of water. So, you may have to do some math depending upon the size of your fresh water tank. If your tank is 60 gallons, then you'll add only 1 cup of bleach for your entire tank. Here's how to do it.

First: Connect your outside shower to your water spigot (in) outlet and flip the valve to (fill). (Montana's and Avalanches have the outside shower with the blue coiled hose. Connect that hose to the outside shower and the other end connect to the garden hose -- fill -- connection).

Second: Set your water heater in by-pass mode.

Third: connect a hose to your winterizing port.

Fourth: mix up a solution of water and bleach in a bucket. Add 1 cup of bleach and the rest of the bucket, add water.

Fifth: insert the antifreeze hose into the bucket, turn on the cold faucet for the shower, and now go inside the camper and turn on the water pump.

This will draw the water/bleach solution from the bucket and pump it right into your fresh water tank.

When the bucket is empty, you may want to fill it again with clear water and let it pump out again. The clear water will flush the water lines TO the water tank. The bleach solution was so strong (1 cup per bucket), this line is now automatically sanitized.

Sixth: Now that you have that 1 cup of bleach inside your fresh water tank, go ahead and fill the fresh water tank as normal until water spews out the over flow.

Seventh: Keep your water pump active and run some water through each of the faucets (hot and cold) in your camper until you smell the bleach water coming through.

Eighth: Let the bleach / water solution sit in your water lines for several hours. Of course the thinner the bleach solution, the less potent the sanitization will be, the longer it takes. A stronger bleach solution won't hurt anything and will require less time to sanitize.

Ninth: Run all the water out of your fresh water tank, and fill it up again. Run some fresh water though all your lines to flush out the smell and taste of the bleach.

Tenth: Resume normal usage of your water system.

(Note: If you want to sanitize your water heater, keep the water heater in by-pass mode and drain it. After you have filled your fresh water tank with the bleach/water solution. then take the water heater off by-pass and fill the water heater from the fresh water tank. Let the water sit for several hours in the water heater. When done, drain the water heater and flush with fresh water. Make sure to take the water off of By-pass).

[dutchmensport]

The_Other_Aaron,

I noticed in your photo you have the grey water valve in the open position. Tip! Tip! Tip!

Never leave your black water OR your grey water valve open all the time. Dump the black and grey water tanks only when they are full or near full. If left open, the black tank will accumulate "stuff" on the bottom of the tank as there is not enough water to flush everything down stream. In the grey tank, crud (especially the kitchen) will accumulate in the bottom of the tank also and in time the smell will be awful. Grey tanks smell worse than black tanks.

The secret is to keep those drain valves closed and let the water flush as much as possible out. Start your new camper out right! Keep those tanks healthy from the very beginning, even if you are parked at one site long term.

Just a little tip and word of advise!

Happy camping!

Watch this video. It explains why:

https://www.youtube.com/watch?v=fs7YE9hmD7k

[The Other Aaron]

Thanks to you all for your responses. This is a 2022 Avalanche 390DS. I like the solutions you provided and I'm going to use them. I'm still curious about that "extra", unlabeled water inlet port. If anyone has ideas on that I'd love I hear them still. I may just have to try to peek behind the wall in the basement (which is all filled up). Or see if there's anything visible from underneath.



For those who caught the open gray valve, you have keen eyes. It just so happens that I was out there at the time to drain that and decided to take the picture. Your counsel has not fallen on deaf ears, although I have already been cautioned against leaving these valves open. I'll just keep that as added testimony to reinforce what I've learned.



A couple of follow up questions: I'm considering keeping the fw tank full for such situations as emergency outages may yet happen in the future. Are there any recommendations for how long to keep it in there between emptying and refreshing? Or, is that a bad idea? Or, is there some safe, natural additive I can put in there to keep it fresh longer?

[dutchmensport]

Originally Posted by The Other Aaron

...recommendations for how long to keep it in there between emptying and refreshing? ...

There are a lot of variables that determine how long water will stay fresh and it's really hard to tell. Actually, water itself never goes bad. What does happen is the bacteria growing in the water that becomes overpowering, or the dirt in the water that makes it unsafe. Water is water, it never goes "bad".

So, the secret is to determine what a safe span of time before things start growing in your tank. That will depend upon the ambient heat (or cold), and the "quality" of the water you are using. I say quality, but remember, it's the "stuff" in the water that's bad.

A good water filter will clean out the "bad" stuff, but not always unless you have a very powerful filter (like the filters they use in water bottling companies and companies like Coca Cola).

If you keep water in your fresh water tank for emergencies, I would recommend at least once a week, simply turn your shore water spigot off and turn on your water pump until your tank goes empty. Once it goes empty, fill the tank again, turn off the water pump, and use shore water again. This way, your water will always be "fresh".

In time, you might find it more beneficial to simply use your fresh water tank all the time. There's no danger of campground over-pressure running from your fresh water tank (pump), and if you ever sprung a leak, you'll hear the water pump kick on and you know water is running somewhere where it should not. I've caught my toilet running, I've caught drips at my water heater anode rod plug, and I've caught drips on my low point drains, and faucets that were not turned off ALL the way because the water pump would kick on and sputter and shut off.

Anyway, short answer .... new water weekly and you'll be fine.

(But, don't simply drain it on the ground. Actually use it. If you don't want to drink it, then at least use it for flush toilets and taking showers. You can flip the water tank pump on and off and turn the garden hose spigot on and off and use up the water in the tank this way.)

[Mikelff]

I use a large funnel and a 4 foot tube/hose that I run into the fresh tank overflow outlet, making sure the hose makes it to the fresh tank. I put the bleach in a 1 gal plastic milk jug, fill about half way with water, and dump into fresh tank. Fill tank, run through all water lines till i smell the bleach. Let it set overnight. I then empty fresh tank and refill tank. Flush all the lines and empty tank again. Done. I keep tank empty till my next trip.

[Rolling_home]

Not familiar with your set up, but on my Cougar 26RBS, the 2nd inlet is for my black tank flush.

[Alibaddy]

2021 Alpine 3650 RLS Fifth Wheel
I also use the winterizing system to pump chlorine sanitizer solution to the tank. However, I often wonder if I am causing any accelerated deterioration of gaskets or other components in the 12 volt pump. I haven't checked whether it is a diaphragm or centrifugal pump. In the case of the former, the diaphragm might not tolerate the chlorine at a higher concentration. I would love to hear from anyone who knows the specifics of these pumps.

[jam115]

Originally Posted by The Other Aaron

I'm still curious about that "extra", unlabeled water inlet port. If anyone has ideas on that I'd love I hear them still. I may just have to try to peek behind the wall in the basement (which is all filled up). Or see if there's anything visible from underneath.

I have a 2023 Avalanche 378BH. Similar layout to your 390DS, except I have a bunkhouse in the rear instead of a second bedroom suite.

Like me, you probably have five waste tanks - a black tank and a gray tank for each of the two bathrooms, and a gray tank for the galley. The 'unlabeled' inlet (the one at the top) should be your front black tank flush, and the one below it (the one with the 'tank flush' label) is for your rear black tank flush. At least that's how mine is hooked up, yours may be reversed so make sure you know which is which (so you don't accidentally overflow your black tank and make a big mess!

[dutchmensport]

Originally Posted by Alibaddy

2021....
I also use the winterizing system to pump chlorine sanitizer solution to the tank. However, I often wonder if I am causing any accelerated deterioration of gaskets or other components in the 12 volt pump....

No, it will not hurt the pump IF you follow with some fresh water to rinse the pump itself. out. But, here's the thing.....

When you add the solution to your fresh water tank, the solution in your fresh water tank now has a mild bleach water solution, and that same water pump will be pumping the water/bleach solution from that tank to all the faucets on the camper.

So, if you add the bleach solution with the winterizing port, then add the rest of the water from your "fill" via a garden hose, then immediately pump the solution from the water tank through the rest of the lines, that is purging out the stronger solution from the pump. When completely adding filling each line with the sanitizing solution from the fresh water tank, then do one more bucket of fresh, clean water from a bucket and pump it into the fresh water tank via the sanitizing system. This will rid all bleach from the water pump.