??? about the fresh water, black water and gray water holding tanks

I am new to the rv lifestyle.  I admit after just one camping trip I am checking this website, looking at maps etc because I can't wait to get out on the road again (dh has to have surgery so we are "here" for a bit) anyway here is my question.  Is there any reason to travel with our holding tanks full if we don't use them on the road?  When we travel we only stop at rest stops and use those restrooms.  ON our camping trip we didn't use our facilities until we were hooked into the water and sewage supply at the campground.  I admit flushing out black and gray water tanks seems a bit daunting to me to begin with. 

The other question I have is since this is a "new" to us tt how do I know if these tanks were flushed out and cleaned out to begin with?  If you are hooked up to sewer does the black water and gray water pass thru these tanks on their way to the sewer?  Is there a procedure to "clean the tanks out before you unhook your sewer lines besides flushing the toilet several times?  (I sprayed Clorox clean up into the bowl and swished it around to disinfect it.  After we left I still don't know if this is what I was supposed to do.  Any and all info will be greatly appreciated

Holding tanks don't need to be full. As far as black and gray tanks go, you want a few gallons of liquid in them to help keep the dump valve seals from drying out and to help dislodge anything in the tanks that might be clinging to the sides or bottom. Fresh water tank you usually want some water in it in case you want to get a glass of water or use the toilet, etc while on the road. Generally you don't want water to just pass through the gray and black tanks. Let them fill up to at least 2/3 to 3/4 full before dumping. Dump black first. If your rig has  a sprayer attachment to help keep the black tank rinsed down, use it after dumping. You will never get your black tank "disinfected", ever. Once waste goes into it, that's it. All you can do is manage the waste (and any odors) and any little bits that are in the tank. Some, like us, use a tank treatment chemical (one of the enzyme type ones) to help break down the solids, others use dish soap, pine-sol, among others. Allow the black tank to fill to 2/3 to 3/4 full before dumping. It helps move the solids along and out of the tank. Use that tank sprayer if you have it. Gray tank doesn't really need much care but dump it after dumping the black tank. It helps clean the drain hose and drain line the hose connects to on your rig. You can use the tank chemicals on the gray tank too, but there usually isn't much to have to break down like there is in the black tank.
Welcome to the RV lifestyle. It really isn't that hard, and luckily with this site and others, there is a ton of helpful information.

The tanks don't require any special attention. Once connected we leave the grey tank open and allow the black to fill to 3/4 before dumping. The black should have several gallons of water put in once dumped. Never leave the black open as the liquids drain and the solids will dry out and plug things up. Plenty of water is the secret to problem free black tanks. We never use chemicals and have no odor problems.

If you have a spray connection for the black tank it is a convenient way to rinse and then add water.

Welcome and good luck,

Ernie

We always traveled with some fresh water onboard "just in case". Might need to use toilet where there is none, or might need some water for the tow vehicle radiator, or might even get stranded somewhere due to breakdown, weather, etc.  It costs nothing to have  several gallons of fresh water with you, and in most cases costs practically nothing to have the tank more-or-less full.

Personally I would sanitize the fresh water system when I take possession of any RV, new or used. It's easy and then you know you started out right.

As far as "cleaning" gray and black tanks, that's almost an oxymoron.  Nor is there any reason to be concerned about it. Do you clean your sewer pipes or septic system at home?  There are traps or check valves in the waste system top keep odors and such away from the interior.  As for dumping the waste tanks, it's a good idea to flush them with some fresh water if available, just to rinse away any remaining solids (including food waste in the gray tank), but it's not a religious requirement.

I personally dont leave any valves open on either the gray or black tank. When the gray tank gets three quarters full, I drain my black tank, then my gray to help rinse the hose. My belief is leaving any valves open, creates the possibility of gasses from the campsite septic entering my rv. In theory there are p traps, but why not just drain the two together. When we travel, we dont even hook up the sewer or water, unless we are getting down on fresh water.  At that point, the bulk of the water used is in the gray tank, due to dish washing, showers, etc. Lots of people leave their gray valve open. I personally think it better to leave both shut. Rule number one, is never leave your black valve open at a campground. When you flush, you are getting straight venting from the septic into your camper. Also you are letting all the water out of the tank, so when you use the toilet, the crap is falling into a dry tank. This is how you get the pyramid of poop. After dumping your black tank, always add a few gallons of water to the empty tank. Your rv waste system does not work like your waste system at home. The home system is designed to carry the waste away with the water. Some people will counter my statement and tell you to leave a dip in your waste line connected to the camp sewer to act as a trap and stop gasses from coming up the pipe. Most campgrounds do not allow this, and insist on you having fall from the camper to the waste receptacle. Draining an rv only takes a few tries to master. Look up a few utubes. Its easy. You will be a pro in no time. Have a pair of gloves handy in the sewer bay. cheers.

We leave home with a full fresh water tank and empty waste tanks (except for aforementioned gallons in black tank).  We fill water when it gets to about a half tank and empty the waste tanks when they're full enough to flush well.  Agree with Gary; sanitize the fresh water tank before using it.

ArdraF

If you really want to clean the black tank, follow the basic GEO method.  You can find insteuctions all over the internet.
Basically, cup of Dawn dish soap, cup of Calgon water softener, 10 pounds of crushed ice.  1/3 fill with water and go for a 20 mile drive.  Dump, done!

Welcome to the forum!

I will add my voice to the choir.

Sanitize Fresh Water system.  Add at least ? cup of bleach to each 10 gal of fresh water tank plus hot water tank capacity.  Fill fresh tank.  Turn water heater off and drain, then close.  Run water (with pump) out of EVERY FAUCET in the camper, both hot and cold, until you smell chlorine.  Hot water will take a while to fill the tank.  This includes the shower and outside hose.  Wait a day, drain everything and refill  and flush until all chlorine odor is gone.  Repeat annually.

Gray tank.  Many good ways to care for this tank. 

Black tank  NEVER LEAVE DRAIN OPEN!!  As stated, solids collect and liquids leave, creating a pile the consistency of concrete in the tank.
Only empty the black tank when it is ⅔ full or more.  Add water to this level if needed.  Drain Black tank, then flush if you have the ability.  Drain gray tank to flush the hose.  CLOSE BLACK TANK VALVE and add a few gallons of water to welcome new deposits.

Travel with at least some water in the fresh tank for emergencies.
Travel with empty black and gray tanks (except for initial welcome water) whenever possible.

One other thing to do is when flushing the toilet, try to remember to shut the vent fan off. This will minimize the chances of the fan sucking gases from the black tank when flushing.

Another thing I did was installed a twist on valve on the end of my sewer pipe. This serves 2 purposes:
1) It serves as a backup valve in case one of your other valves leaks a little.
2) When I let my black tank fill to at least 2/3 full, I fill my gray tank all the way. Then I dump the black tank till it's empty. Then I shut the new twist on valve and open the gray tank valve to let some of the gray water into the black tank. Let it run until the water level equalizes. Then shut the gray tank valve open the twist on valve and dump the black tank again. Then what ever water is left in the gray tank, use it to flush the sewer hose.

https://www.walmart.com/ip/Valterra-T58-Twist-On-RV-Waste-Valve/55356052?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227066302692&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=c&wl3=170960829810&wl4=pla-278526707977&wl5=9002443&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=online&wl12=55356052&wl13=&veh=sem

Another reason not to leave the dump valves open when connected to a sewer are sewer flies.  I got a dandy infestation one time that let tiny flies into the RV every time I flushed the toilet.  Not fun - I wound up "bombing" the tank with Raid, then flushing it thoroughly to get rid of them.

Since then I leave a low point in my sewer hose to form a P trap and provide a water barrier between the trailer and a strange sewer system.  Some areas require a straight drain from the RV to the sewer but I'd rather argue with an inspector than have to deal with another fly infestation.