how much water do you leave when storing

[pmaen]

Just wondering how much water you leave in your black and gray tank when you store. We live in California and it is pretty dry, and sometimes we don't take it out for three months or so. I always try and go check the level of water in the toilet to keep the seal wet, but not sure I am leaving enough water in the black and gray to keep from drying out. Any suggestions how to make sure?

[Soppy]

I completely drain my tanks when I return from a trip.

[astrnmrtom]

Usually empty. In freezing temps I'll pour some RV antifreeze in the tanks and the toilet bowl.

[Duster73]

Between trips I fully dump both tanks then add 3 to 5 gallons of water to the black tank with an additive. Then a gallon or so in the grey tank. Fresh water tank gets dumped after each trip. This is usually not much water.

When I winterize I add a gallon of antifreeze to each tank and a little to the traps. Then completely empty fresh water tank. But I am in MI so this part might not apply to you.

[RVFunlovers]

We tend to use our coach often. We dump at the campground but often use some water on the trip home. I do not have an easy way to dump at home and it has not bothered me to leave the gray or black tank for a month or so. If you are going to winterize then it is best to start empty.

If I leave the coach for more than a few weeks we dump the fresh water when we get to a RV park and refill it fresh.

[macnut]

We keep a full tank of fresh water most of the time, as we camp almost every month. A few times a year we skip a month. To keep the water fresh and our tank in pristine condition, we add Purogene when we fill the tank. It takes an ounce for each 30 gallons. You can get it on Amazon or at rvwaterfilterstore.com

[NLOVNIT]

Short term/during season, 2-3 gallons in both the black & grey along with additives, fresh about 1/4 tank. Long term/winter storage, empty & winterized.

[UFO Pilot]

A few gallons in the black and gray tanks. I store the MH with a full tank of fresh water and a full tank of fuel. We live in earthquake and wildfire country so we are always ready to bug out if necessary.

[mmartin_tdc]

I do similar to UFO Pilot. about 4-5 gal in the black tank, with additives, empty grey and galley tanks, pretty full fresh water tank. I do a good rinse out after each trip so tanks don't get nasty.
I live one county east of him in Solano County.

[Mudfrog]

I never purposely add water to the black and gray tanks after dumping. I rarely use any treatment. I have no idea whether the holding tanks dry out or not and I really don't care.

[Country Road]

After reading the replies and seeing what is being done, I personally conclude that there is no steadfast rule on tank maintenance. I give everyone the permission to continue to do what you’ve been doing. The tanks seem to be very resilient and can probably stand whatever is thrown at them.

[Gary RVRoamer]

I always try and go check the level of water in the toilet to keep the seal wet, but not sure I am leaving enough water in the black and gray to keep from drying out. Any suggestions how to make sure?

A piece of Saran Wrap over the toilet bowel will greatly reduce loss by evaporation while in storage. Another trick is to trickle a couple ounces of vegetable oil into the bowel so that it floats on the surface, reducing evaporation (but it can leave a messy ring).


I wouldn't obsess about residual water in the waste tanks. Leaving a couple gallons in each is a good practice, but hardly critical. The tanks are relatively immune to evaporation anyway - the only opening is the vent pipe. Every other path has either a valve (the toilet) or a P-trap (sinks & shower).

[Dutch Star Don]

We use our coach year-round. The longest it may sit is two months. Both our toilets are macerator toilets, so lots of water is used. At our last overnight stop, I dump both tanks and then whatever is used on the way home stays in the tanks until the next trip.

I've been RVing for over 45 years and in the first half of those years I obsessed with cleaning the tanks after a trip. The reality, there is no need to. Once a year I pour a bottle of grey tank cleaner in and that's it.

The freshwater tank is always kept full as we live in earthquake country. I haven't drained a freshwater tank in 30 years. I've never sanitized one in 45 years. Never ANY issues.

[Camp CA]

In 18+ years I have always drained my black and gray tanks when the trailer and motorhome are stored in California. No issues.