Fresh Water Tank loses water while traveling

[Danbury Sue]

We have a 2018 Cherokee V274 - when traveling, our fresh water tank loses up to 1/3 of a tank when traveling over 200 miles - anyone have any suggestions to stop this?

Thanks!!

[Kimber45]

I had a problem with my fresh tank siphoning off. after filling and water starts coming out the over flow tube it continues to drain tank. I added screw on caps to my over flow tube. I remove them, fill tank. when water starts to drain off I shut water off and screw cap on. ***don't forget to remove before filling****

[birdman77]

I did something similar...I put a ball valve on my overflow... Only use it while traveling.