Thanks a bunch for that . I am thinking my RP177 holds about 17 gallons including the  hot water tank so 1/4 cup should be about right unless I hear differently from someone .

The reason for this variance is that time of exposure plays a big part. Lesser amounts of bleach simply require, within reason, increased length of time for the bleach to do it's thing.

EDIT 

I'll join the others in being shocked if you have anything other than a 30 gallon fresh water tank.  As someone else said, time is a factor in the equation.  Half a cup of bleach in 30 gallons for 4 hours I think.  A cup up bleach for an hour maybe.

The "spam" thing happens, in my experience, when you have a slow connection and try to re-post a message that seems like it didn't post but it did.

TT

According to the Q&A on Amazon the manufacturer says:

here's the MSDS for Spring Fresh

https://images.homedepot-static.com/catalog/pdfImages/00/00ff0197-dd95-4cd4-80a7-9f04173212b2.pdf - https://images.homedepot-static.com/catalog/pdfImages/00/00ff0197-dd95-4cd4-80a7-9f04173212b2.pdf

its only about 4% ethyl alcohol so 80 proof vodka contains 10X the alcohol. You'd only need less than a pint of vodka to be the equivalent, so you could drink the other 7 pints after which you wouldn't be worried about what the water in your tank tastes like 

I looked up the SDS on Clorox and it's quite similar to the one you listed. 

Not sure what you mean by similar?

Bleach is sodium hypochlorite, the Camco stuff's active ingredient is alcohol. Totally different chemically. Beach is considered hazmat, Camco's product is not. The bleach is more dangerous if you get it in your eyes and is highly toxic to aquatic life. Its a very well proven sanitizing agent though (maybe because its toxic to aquatic life?). 

But lots of stuff will have very similar reading health precautions on the MSDS:  avoid eye and skin contact, don't drink it, don't pour it in lakes or streams.Mostly common sense type stuff. 

For myself, I live next to a wetland area so I don't like to dump out any chemicals. Amphibians in particular are super sensitive, and I like to hear my frogs at night. So, for myself I just rinse my tank with plain water and don't drink out of it. 

Camco Drinking Water Freshener -- Keeps Stored Water Fresh Tasting & Odor Free

Contains: Sodium Hypochlorite solution CAS # 7681-52-9

Directions:

1.Fill tank to 1/4 total volume.

2. Pour 1 oz. Drinking Water Freshener into tank for each 20 gallons of tank capacity.

3. Complete filling of your tank.

What is not specified is the Sodium Hypochlorite concentration. However, for a 30 gallon tank, 1.5 oz. of this is used. The bottle is 16 ounces so that means there is a little over 10 tank fillings that can be done with this bottle. The French instructions give the metric measurements as 30 mL for each 75.7 L water.

I would not trust isopropyl (rubbing) alcohol. It isn't as toxic as methyl alcohol, but it is still toxic. I would not trust it in my water system, even if I were flushing it out.

https://difference.guru/difference-between-ethyl-alcohol-and-isopropyl-alcohol/ - https://difference.guru/difference-between-ethyl-alcohol-and-isopropyl-alcohol/

Looks like there are two different Camco water freshener products. I think mjlrpod is using the Spring Fresh material which is alcohol based. This product looks to be bleach. 

One problem with disinfecting tanks where water sits for awhile is getting rid of the biofilms. Given time, bacteria grow colonies which cover themselves with a protective layer of fatty material.   Once they do that they're very hard  get rid of. That's usually the cause of the slimy film you feel on containers if you leave water in them for awhile.

I'm guessing that's what the surfactant is for in the Spring Fresh stuff, the alcohol probably isn't going to work well on the biofilms. Bleach does well in high enough concentrations, if you leave it long enough. 

I had a wood hot tub I tried a bunch of ways to disinfect. You can't use bleach/chlorine in strong enough concentrations long enough because it damages the wood. More gentle oxidizers like hydrogen peroxide don't cut through the biofilms.  The best I could ever do was to drain every couple of weeks, scrub the biofilms off with a little detergent, rinse and drain again, then refill, and use hydrogen peroxide as a maintenance oxidizer in between. The scrubbing never got rid of everything and in a couple of weeks the films were always back, but that was with 103 degree water which bacteria think is heaven. I  finally got rid of it, too much work and water waste.

Just as a reminder, there is a simple solution to all this worrying about sanitizing. If you don't drink the tank water, its all good....

Food for thought:  If you leave water in the fresh water tank for any significant period of time, it will sit at the perfect bacteria growing temperature.  It is impossible to truly sterilize a fresh water tank no matter what chemical concoction you put in it.  You may be 100% successful of ridding all the bacteria at the point of cleaning it, but the moment you open the filler port and start filling it with your drinking water only hose, you've introduced new bacteria in it.  With a near perfect growing medium, they'll be back in no time and will have established a nice thick biofilm.  If you have a strong immune system and you don't introduce potentially lethal bacteria into the tank, you'll probably not get sick drinking the water but keep in mind that water borne infections are the biggest single killer of mankind in the world.  

This is true as far as it goes but we must keep things in perspective. 

Germs are all around us, and in us. 99.999% of the time or more we get along quite well, there are only a few that cause problems and its extremely unlikely that we would introduce those bad guys into our white tanks, assuming the water is 'potable' - and that is obviously the only water we should be introducing. 

It takes quite unusual circumstances - Water just sitting in the tank for a prolonged time and consistent high temperatures (as in the summer in the desert southwest), for any bacterial sludge to form. If we avoid either one of these two extremes, we'll be ok. 

The 'plastic taste' of the tank is a totally different situation, unpleasant to some but not at all hazardous.

I come from the mid-west where hard, strong tasting water is the norm, even before chlorine and such are added. I also have years of tent camping where ANY potable water, no matter how 'awful' tasting was sometimes a blessed event. 'Sulphur Springs' in the past, with their truly awful tasting water, were felt to be medicinal for many years and drunk without any harm. It would be very unfortunate if 'newbies' came to believe that 'plasticy' tasting tank water is harmful. It isn't.

You have an expertise in the law. if we have a legal issue, we should listen carefully and respectfully to your views. Biology is not the law. If you can provide us with a reference from the scientific literature supporting your views on microbiology, please do so. I know of NO controversy about the potability of rv tank water if it turns over at a reasonable rate, in my experience in temperate areas even once a year. I have no experience in Sahara conditions, but it seems to me unlikely that, even in these very hot conditions,  a minimum of even once a year would not suffice. If others have had bad experiences with their water in hot climates from bacteria or fungi growing in it, it would be very helpful to hear what they have to say.

Those who believe in the safety of drinking tank water will continue until they have a reason to change their minds.  Those who avoid drinking tank water are unlikely to start, and certainly not based upon the information you provided about mid-west water.  

By the way, if you Google contamination of food and water by plastic containers, such as polyethylene, you may not be as confident about plastic taste.  But what the heck, even those us who are drinking water from other sources, usually store it in some kind of plastic container.  As Country Joe and the Fish sang in the Vietnam Rag:  "We're all gonna die!"

One park I camped in last week had warning tags on the potable water spigots advising pregnant and nursing women not to drink the water. High Nitrate levels.

High nitrate levels cannot be 'fixed' by filters and chlorination.

Makes me wonder what is in campground water that we don't know about....

I'll stick to drinking bottled water and tap water from trusted sources.

There really is no impasse here, its a personal choice. I look at it this way:

If you

are concerned about sanitizing properly or

don't like to contaminate your local environs by dumping your sanitizing solution on the ground or

are concerned about the quality of the tap water you might get travelling or

want to increase your stored water supply beyond the measly 30 gallons or

are not accustomed to drinking tap water anyway or

all of the above (me),

then bring and drink bottled water. If none of the above are issues for you then feel free to drink water from the tank.  No problems either way, and certainly no reason to argue about it. 

'Quartzsite Crud' is a thing around that area every winter, and it's pretty common among the snowbirds...all kinds of bugs and ailments travel along with the RVers as they arrive and shake hands and share food, utensils, etc at potlucks and gatherings.

One thing I noticed in our 'tribe' of about 25 people.....only two people caught the 'crud' and I know for a fact that they drink and cook with the water they pump into their RV fresh tank from the available spigots. 

I don't understand the worry.  My city water is chlorinated.  It sits in my pipes, both copper and plastic, until used.  Biofilm is probably growing in the plastic pipes as we speak.

I sanitize my RPod tank before each season with a half-cup of unscented bleach, fill the tank, and then drain it.

I fill my RPod tank before a trip with my city water and drink it.  I don't get diarrhea and it tastes like home.

I think this is unnecessary worry along the lines of antivaxxers.

Where untreated water is put into the tank, the odds of excessive bacterial growth increase along with the risk of becoming ill.  It is all a function of odds or probability.  And each person has her/his own tolerance for risk not only from a point of view of choice, but from a physiological point of view as well.  Some have a higher resistance to water born bacteria; some not so high.  

And there is no guarantee that if you drink campground water, whether put into your FW tank or into separate water bottles that you are going to be free of risk.  I recall reading some comparison tests of San Francisco municipal water compared to bottled water.  The San Francisco municipal water was considerably more pure for both chemical contaminant and bacterial count measures.  In many parts of the country, healthful potable water is getting harder and harder to come by.  

The whole water issue comes down to personal preference.  If you like the water from the FW tank, drink it.  If that risk is unacceptable for whatever reason, don't drink it.  Unlike not getting vaccinated for measles, you're not going to make other people sick by drinking tank water. 

It's kinda like asking which motor oil is best....

Agreed. 

Thinking about this, the desert southwest is probably the most difficult area for any of us to be definite about.

For newbies, just for perspective on changing drinking water in tanks - 

http://blog.quickrvinsurancequotes.com/need-sanitize-my-fresh-water-tank-rv/ - http://blog.quickrvinsurancequotes.com/need-sanitize-my-fresh-water-tank-rv/

and 

https://campergrid.com/keeping-rv-water-fresh/ - https://campergrid.com/keeping-rv-water-fresh/

Jeeze. 

I read thru that entire process of sanitizing the fresh tank. Holy Moly.

That's a LOT of  work compared to just carrying around a few gallons of actual drinking water. I mean, why is it SO important that your drinking water comes from your pump operated faucet as compared to a gravity dispenser on the counter or floor?

Using the so called 'fresh water' tank just for showers and toilet use means you are not having to sanitize water and the tanks to the utmost level of sterility just to flush it down the drain. I'm guessing here, but I bet 90% of that 30 gallons ends up in the toilet, the shower, washing dishes, maybe hosing off muddy shoes, or washing the dog. 

In my opinion (and I've been doing this for more than 25 years) ANY water that goes into ANY RV fresh water tank is, from then on, NON-POTABLE. Period.

It's for toilets, showers, and washing dishes.

It occurs to me that one of the reasons we are blessed with relatively good senses of taste and smell is that it give us a survival advantage.  If something tastes bad or smells bad, it's a warning to us that it's probably not very good for you.  When water tastes bad it's a warning to your body to stay clear of it, ergo the use of the terms "bitter water" and "sweet water."  One may make you sick while the other is less likely to introduce you to new little friends.

Originally posted by podwerkz That's a LOT of  work compared to just carrying around a few gallons of actual drinking water. I mean, why is it SO important that your drinking water comes from your pump operated faucet as compared to a gravity dispenser on the counter or floor?

Space and weight.

Carrying extra water in a container or bottles takes up both. I have a tank that can suffice for use if properly sanitized and potable water is used to fill it. For extra safety, some Camco Drinking Water Freshener (essentially bleach) can be used to ensure safety.

I spent 26 years in the Army. I have had to drink water from Water Buffaloes (wheeled tanks) and Lister Bags. Drinking water from them did not make me sick or kill me so I think I can safely drink water from the fresh water tank. Field Sanitation classes provided training in how to keep potable water safe so I feel confident in using my  RV's fresh water tank.

A lot of this comes from personal experiences. I spent 35 years doing lots of international travel, much to places where people would think you're crazy if you suggested drinking or brushing your teeth using the water from the tap. So, I just learned to assume its all contaminated and never drink from taps, either at home, in hotel rooms, or in my RV's. For me, its not at all a hardship or even an inconvenience, its second nature. 

None of us are ever going to convince the others that our way is better. This is a matter of choice based on experience, and what each individual feels is most convenient and sensible for their needs. 

I see a possible scenario where all of your potable water is only in the fresh tank. Showers are taken, toilet is flushed many times, water is used for cooking and cleaning, outdoor showers, etc, and one HOT day, the pump runs dry, the fresh water tank is emptied, and you now have ZERO drinkable water!

To prepare for this, I suspect you carry a few bottles of separate drinking water, having been in the military.

BTW thanks for your service!

Yeah carrying 5 gallons of potable water in a seperate jug means you can deduct that weight from your fresh tank when traveling, by filling it less. In fact, I only travel down the road with my fresh tank showing 1/3 or less...weight is an issue with these. 

Thanks...

This will flush out any bugs or debris. 

I've been drinking hose water for nigh on 70 years and I ain't died yet.  Just let it run until the hose smell went away and the water was cool.  My worries are where the water comes from that goes into the hose. 

Might have sounded...I dunno....suggestive...but was not intended to be.

Anyway, yeah a short 'pigtail' of garden hose works well.

At the female end of the hose, cut about 18" or so down from that end. 

Of course, you can always attach a new replacement female end to the long section so you have a good hose with both ends.