Two Questions (Sanitize and Empty Tank)

Okay, black water tank gauges are inaccurate. How do you check the level before it becomes a problem?

I sanitize the fresh water system in our teardrop twice a year. This last time I added a step after chlorine and rinse, in using dish soap, rinse and finally baking soda which also purifies and deodorizes and taste.
In each step the water heater is drained.

When I first went to a TT instead of a tent, the water storage was a BIG concern to me because I got ahold of some bad water on a backpacking trip to the Grand Canyon and got a good dose of Guardia. A water born bacteria that I would not wish upon my worst enemy. Anyone who has had Guardia knows what Im talking about. Any how, I searched the web and found a newsletter from the Dept. of Health and to summerize.
1. 1/4 cup of chlorine bleach per 15 gallons of water, unscented bleach, pour into bucket with 2 gallons water and let sit for 30 minutes, never said why. 2.Pour into fresh water tank,fill tank with water, flush all water spigots in camper and let stand for 24 hours. 3. Flush system until you can no longer smell bleach.
It is recommended that water sit in fresh water tank for no longer than 6 months without usage.
I have followed this advice for a long time with no problems yet. Personally, I would not let water sit that long. 30 days is my max and then I drain everything and refill with fresh water. But am always camping every other weekend so no worries.
Happy Camping.

Maybe I'm the exception to the rule, but I've had no issues maintaining the accuracy of my tank indicators in my 2012 TT. The black tank indicator does get hung up sometimes, but after a good rinse it usually clears it up, and if it doesn't I chuck about 10 pounds of ice cubes into it with it full of water and drive a couple of miles and it clears it up. I use Happy Camper and Kirkland toilet paper. It helps to use a lot of water when you flush- you want to use more than you think you do, and you still won't fill it up. Our 30 gallon black tank will last at least 10 days of full time use with our family of 3.

Muddydogs wrote:
... Most city's chlorinate the crud out of there water which in turn is going into your holding tank taking care of anything that might be in there.

Um, not so. Yes, they chlorinate, but the residual is only barely enough to deliver "sanitized" water to your tap, if there is any at all. As a pool owner, I test to keep my pool at 2-3 parts per million of chlorine. Tap water tests out at zero. Probably not actually zero, but the test kit doesn't measure such minute amounts. Case in point - on a warm day, if I fill the pool using municipal water, it can cloud up in as little as a half-day from bacteria, if I don't add additional chlorine. RV systems aren't open to the world, so there is little contamination to encourage growth, but neither is there anything left in tap water to discourage it, either.

BTW - fun fact: Chlorine itself has a pretty weak smell. When it combines with other chemicals ("bugs", etc.) it produces chloramines, which have a very strong smell. That's one of the clues that a swimming pool needs MORE chlorine, as the active stuff has been used up. It's easy to get to very unsafe levels in a pool ("shocking' the pool), and not have any smell at all.
In the RV case, smelling it coming out of your taps is the indicator that it's done it's job. And yes, regular bleach smells, because due to dilution, storage, and age it already has formed some chloramines in the bottle, along with the more concentrated "active" chlorine.

I pretty much agree that regular sanitizing is not needed. But when I bought a used trailer, I sanitized the FW tank. Who knows what the previous owner did. When I bought a brand new trailer, I sanitized the FW tank. Who knows what was on the hands who did the plumbing.

Once I have taken control, I keep some water in the tanks at all times. It is part of my emergency supply here at home. (we don't winterized here in So Cal) If the trailer has not been used for a few months, I just drain and refill. I know there won't be anything to worry about in my tank, and if there was the fresh city water will kill it.

The black tank part has been answered, but I'd add this about sanitizing the water:

While generally you are dealing with a mostly closed system, after a pretty short period (a day or less), any treated water can have whatever sanitizer in it degraded/used up (usually a very small amount of chlorine in a municipal system). Even a bottle of pure bleach loses it's ability to sanitize moderately quickly after opening. So, start off the season by sanitizing the entire system, just to get it as sanitary as you can.

Water in the system can get a bit funky after some time left standing. How long depends on the source, and the temperatures. If you are only using "city water" from campgrounds, just run the taps for a bit when you first hook up. If depending on your water tanks, drain them if they will be unused for a period of time (I do it after every trip). Note that the hot water heater stores a few gallons, and it can take a lot of flushing to cycle new water for old. I also drain mine, if I won't be using the camper within a week or so. This can be one major cause of the dreaded "sulphur smell" that occurs in hot water lines. Those bugs just love the toasty warm heater water.

The good news, if you are using "city water" either directly or from your tanks, there's nothing bacteria-wise that will make you sick. Worst is that it may smell or taste icky if it does grow something due to disuse. Well water/lake water from a "low overhead" country campground can more suspect, but even there, the "bad" things, like e. coli, don't grow well in the kinds of water systems used in RV's. So if you didn't get sick while camping, you won't afterwards.

1. I would just use liquid bleach. I use 1/4 cup per 15 gallons of water. Pour the bleach in, fill with water, run every fixture until you smell a little chlorine. I usually let it sit overnight, then drain the tank.

2. The tank gauges are never accurate, and the black tank is the worst. No point in trying to clean it, it won't last. You will learn to live without it very quickly. Fortunately the black tanks is always the lowest usage by volume, so it never gets full first.

I would use the recommended method of bleach and water. Chlorine tablets would take longer to dissolve. Just put the bleach in your hose before you hook it up to the fresh water fill.
It's quick and easy.

Many of the sensors in tanks do not work or are not accurate.
Google The Geo Method. That's what I use in the Black/Gray water tanks.

All it takes is a little piece of something on one of the tank sensors for the reading to be off. Might try flushing the tank a couple times or filling the tank 1/2 to 3/4 full the next time you come back from a trip and letting it slosh around good while driving. The wands you connect to a hose and stick down the toilet tend to have a lot better pressure then the tank flush and will cut the crud out of the tank very well.

As for sanitizing the fresh water tank why bother? Keep some water in it during the camping season and empty it before the freeze. Do you fill from a city water supply that has been chlorinated? Most city's chlorinate the crud out of there water which in turn is going into your holding tank taking care of anything that might be in there.