Welcome to the forum from the Space Coast of Florida.
I had this problem but it was in the front. It was due to some of the plastic fitting cracking. I donít live in cold weather so I know it was not a freezing issue. Do you live in a place that has gone below freezing yet?
Mine was caused, Iím sure by high pressure from a campground water supply. I was in a campground and my pressure regulator acted up and allowed the pressure to rise to 80psi. What is your water pressure at your site? If you donít know make sure you use a pressure regulator.
As someone noted, you need to trace water lines. The underbelly that is sagging could be the place to start.
2016 Siverback 33IK, Towed 40K+ miles
2018 Ford F-350 Lariat 6.7L V8 Diesel 4WD Crew Cab
Andersen Ultimate Hitch
RadMini Stepthru eBikes
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