Accidental sewage in grey tank?

[steamboatscott]

For an $885 prep fee, my dealer skipped over several important items on my new RV that I got to deal with on the first outing. One of them was leaving the grey and black tank valves open. This was an unpleasant job to close them and then drain what remained in the dump hose between the valves and the end cap before a discharge hose could be attached. I'm also assuming that sewage got into my grey tank, right? Should I just clean it a few times with dishwashing detergent, or are there other recommendations?

As an aside, I was pretty surprised to see no Google results for people accidentally doing this themselves (leaving both open and getting a mix). Seems like it could be easy to forget.

[ctbruce]

First, do a search for dumping stories. 75 posts in place to put your dumping stories.

Your dealer shouldn't have filled your black tank with sewage to check it. Is your unit new? If so, I wouldn't think it is anything to worry about.

[chuckster57]

Any decent dealership will fill ALL holding tanks with fresh water to check for leaks and proper sensor wiring. They should have been emptied before delivery. We leave fresh tank full to demonstrate water pump, water heater and toilet.

If you took it home and then used it with both valves open and the cap on, there may have been a bit of mixing. I would just fill the gray tank with fresh water, rinse and go on about your business.

[steamboatscott]

I used it this weekend, hence both tanks filling with a mixture of grey and sewage and my problem of closing the valves but still having some nasty stuff drain out when unscrewing the cap before connecting a drain hose. Ended up flushing the black with the built-in hose port and then cleaned the grey with dishwasher detergent then diluted bleach.

[Dave W]

Since there is supposed to be a trap on any sink drain to control odors. not a big deal if there is some intermixing between tanks. A for instance and one of the accepted ways to drain and flush tanks is to dump the black tank then when it has stopped flowing, to open any gray tank valves to do a back flush on that black tank and line. If you have a secondary Valterra gate valve at the drains outlet, it will so an even better back flush --- and maybe just a bit of intermixing.

[packnrat]

it should not be a problem. as the grey tank is not usable water so it is nothing.
just keep your dump valves closed except when dumping. empty the black before oppening up the grey.
if you are worried just fill up the grey and then dump. repete. and all should be good.

[bill-e]

If it were me, I would fill up the grey tank with water and bleach to sanitize it somewhat.

I have experienced the grey water backing up into the shower, or maybe just not draining, when the tank got full during a shower. I'd rather know that I at least attempted to sanitize it a bit.