Could be leaking flush tank depends on model
www.thetford-europe.com
look for 'Ask thetford' drop them a line using online form or telephone them. While on their site click Service Click Repair Instructions then download the sanitation pdf and the others if you want. Look at and down load the 'Troubleshooting' pdf's too. It would be interesting to know what was causing it, so to help others post the solution.
Bob, April 2013
