During the winterizing process antifreeze is poured into each drain. Some of that will make it into the tanks so if there was some liquid left over from the last dump the antifreeze should keep it from freezing. I guess it's possible that just enough antifreeze was used to fill the traps and nothing made it to the tanks.
That's why I do my own winterizing. At least then I know for sure what has been done. If you empty your tanks the last time you are out, then pump anti-freeze through your lines and each faucet, pour some down each sink, shower trap, you will have plenty in each holding tank.
Dale & Carol
2010 CF30SK Patriot
I'm with Dale, I do it myself. True story: picked up new motorhome and dealer had performed fresh water pressure test for all systems. They "thought" they winterized the lines and we left after the PDI. For some reason I noticed a drip from a faucet, it was water! We caught it in time and winterized. Some water turned to slush but I warmed up camper and believe I caught it before damage occured. The test will be in the spring when I perform a pressure leak down with a gage.
2013 Jayco Eagle 334RBTS
Crossroads Forum Lurker