Massive undercarriage leak, when i freshwater flush black and gray tanks

[BlasterPig]

Guys,
New owner of a micro minnie, but when i hook up the "fresh" water to the femaile connector on the side of the minnie to water flush my black and gray (with pull valves open) the water POURS from beneath the carriage. is there a valve or plug in that line before it hits the tanks on the bottom, or could the line be broken. I can't find any diagrams telling me if it is accessible underneath. with check it out as soon as it quits snowing!
BlasterPig out thanks!

[Morich]

Let's do some checking on the process?
When you say hook to the fresh , do you have a separate connection for flushing the tanks, not confusing the input for water to the RV?
We will need more info on year make and model to sort out exactly which RV you have and possibly look at drawings or manuals.
Not looked a a new trailer in some time but I would expect the connection outside to have a valve to switch it from filling the fresh water tank or to go directly inside for use. If this is left in the wrong position, it can fill the fresh water tank and overflow outside.

[BlasterPig]

Thanks Richard. 2017 2106FBS Micro Minnie Winnie. We have separate fresh water fill on rt side of the minnie and a flush 3/4 inch hose attachment on the left side of the minnie specifically to flush the blackwater tank. This seemed to be the source of the water.
Your idea is a good one but it appears this flush line doesnt li k to the freshwater at all. And there was definitely no water flowing through the blackwater tank and out the drain hose.

[Minnie-x]

Hello, new to the forum. I am having this exact problem with my 2018. What was the reason and how was it fixed? Thanks