I have a regular house toilet in my travel trailer. It was installed 4 years ago and I have never had a problem until recently. My daughter and her husband returned to the states after getting out of the army and have been staying with me while they look for a house. The toilet has recently started burping when flushed and empties the bowl of water but will sometimes leave paper and waste behind. I stay in the trailer while working only about 4 months a year but due to an accident I have been here for 9 months with my daughter here for 2 months. The problem started about a month ago. Could the problem be that there is an increase in waste? Any suggestions would be appreciated.

Sounds like a partial blockage in the drain line. Snake the line from the roof vent. Good luck, Tom