How do you leave your tanks?

[Skynardo]

So we are coming off a long road trip and planning on giving our RV a rest for 3 weeks to a month. I plan to dump and thoroughly flush my black tank at our last stop and drain the Grey of course. Then what? Is it better to leave them dry or fill them to one third with water and your normal chemicals/cleaners?

[Ballistic]

That seems like a fine plan. I personally don’t fill any fresh water until departure, but I do add 3 gallons to the gray and black tank after cleaning them solely because I already have the hose out and it’s one less thing to do/remember prior to the next departure.

[Skynardo]

Yeah so fresh water I suppose I should drain and leave open. I always do a sanitize and rinse before filling fresh water for a trip.

[Ballistic]

I wouldn’t leave it open, but a rinse should be all that is needed just to flush the bottom of the tank. Sanitizing is up to you.

[wildmanabe]

i drain it all at CG. then add prob about 5/6 gal water to blk tank along with orange stuff i get at walmart. this way on ride home it gets moved around while driving. i always have some amt of water in blk tank to help keep the solids turning to liquids

[Indy500]

You should always have water in your tanks. Waters your friend, and so is a product to break down bacteria. And over time that water in your tanks will evaporate, you don't want that.

[Mr. Dan]

Originally Posted by Indy500

You should always have water in your tanks. Waters your friend, and so is a product to break down bacteria. And over time that water in your tanks will evaporate, you don't want that.

Really? What if my tanks are empty between trips? Will they disintegrate? or what?

[itat]

When we park the 5er between trips my grey tanks are empty and I leave a few gallons of water in the black tank, usually with a bucket of Geo Method mix.

[5picker]

Drain the black/grey and add back your favorite chemical(s).
In 40 years we have never had to add anything to the grey during or between trips but we're pretty conscientious about wiping off food scraps and grease.

We always have some water in our fresh tank and I only ever sanitize at the start of the season and we simply add to it, when necessary. It has sit for a month or even 6 weeks without issue. I do add an appropriate amount of chlorine or Drinking Water Freshener when topping off.

Same for the water heater... never drained between trips, only at the end of the season.

[Portagie1968]

From the Wild Bunch here is what they do. Black tank - Drain, rinse (with built in sprayer), fill up a little, Drain (do this about three times), let it almost drain dry and then close and wait for next time. Gray Tanks - Add Gray Tank Additive, then some dawn ( so both sit in the traps until next time), drain one tank at a time to rinse the hose (so no rubber gloves needed), then let it almost drain dry then close and wait for next time. Before we take our next trip, a gallon of water and additive go into the toilet for road agitation and extreme emergencies.

[lwbfl]

Some of this is preference and some is luck. I've had RVs that could sit forever with completely dry tanks and never have an issue. Others (current one included) never seem to truly empty the black tank and need to have water in them to prevent odors when flushing. I do leave my gray tank empty, but ensure water stays in each P-trap. I add 5 gallons of water and tank treatment to my black tank, otherwise I get an odor when flushing the toilet.

[CurtPutnam]

Is there any science or engineering for leaving some in the tanks or for leaving them empty? We leave the gray and black empty and try to leave the fresh empty.

[RFSims]

I leave my tanks empty. Fresh water tank empty if no use for 3 months. If I know I will use trailer in a few weeks, I leave full. Grey and black tanks empty. They haven't disintegrated, fell out or exploded. Have done it this way since the 1970s.

[lwbfl]

Originally Posted by CurtPutnam

Is there any science or engineering for leaving some in the tanks or for leaving them empty? We leave the gray and black empty and try to leave the fresh empty.

I seriously doubt it. On my old units the input and output were straight shots so I think they drained more completely. On this new unit, everything has a sloping 90 degree angle and sensors in the line of flow. I'm thinking sediment is getting hung in there with this one, so I need to keep the water and treatment in there so I don't smell it when I flush with a dry tank. I've had 7 others that I let dry without any issue. I'm only referencing the black tank here, fresh is empty unless I'm using it, gray empty with water in each p-trap.

[NMWildcat]

I keep reading about folks leaving their tanks empty and dry.
How do you do that?
I have yet to personally see any RV tank that you can drain completely, although I'm sure it is must be possible with some tank configurations.
My tanks are suspended by side rails, so they all have a 'belly' that holds at least several gallons and the drain outlets are on one end and usually a bit up from the bottom so draining them completely is impossible.
I will admit to occasionally using the LevelUp system to lean the RV to the drain side of a tank, especially when I am trying to drain the most out of the fresh tank. But it still won't be empty
I'm just curious if I'm missing something

[CurtPutnam]

For me, empty means nothing more drains. We do not go to excess to get very last drop and I do like water in the traps.

[Chuck_S]

1. Drain 'em.
2. Forget 'em.

Unless you climb inside the tanks with towels you can't get them clean and dry anyway and an enzyme and Odorlos will continue to digest any remaining waste in the tanks. If you want them to stink use a poison in the tank -- they're usually blue and the prominent smell at Camping World.

It is not necessary to sanitize waste tanks.

-- Chuck

[flyflotrtim]

Tanks should be fine if left empty. However we leave 3 or 4 gallons in our black and grey tanks with a bit of detergent to slosh on the way home and again on the way to the next camp spot to help loosen anything tht might remain. We also like a bit of detrgent in any interior traps.

[PopFla]

I always leave 3 to 5 gallons of water in the black tank just in case there's some....stuff.... still in there after dumping and rinsing. Last thing I want is a nasty crust building up in there in the Florida heat.

[Tom48]

Originally Posted by Mr. Dan

Really? What if my tanks are empty between trips? Will they disintegrate? or what?

I agree with the "leave some water in the black tank" to continually move about and work at preventing dried on ". ".

As for grey -- whatever. But fresh. I always want SOME. Any time we travel you MIGHT WANT SOME. At home, since the rig is in our backyard, a little water will be used. Then I dump it and refill with our very good, lightly chlorinated, city water before our next trip.