RV toilet

one of the more common issues is the flapper not completely sealing. we had the same issue a few years ago and this is the advice we were given which solved our problem.

turn off the water, step on the flush pedal and using something stiff like a wire hanger GENTLY scrape the interior of the slot into which the flapper fits. you'll likely find some crud that is keeping the flapper open.

Hit the pedal a few times and see if the water valve is just sticking.

What can happen is, minerals in the water can get inside the water valve and keep it from sealing. Also, make sure you release the foot pedal abruptly. This allows the spring to get the valve turned off completely. DO NOT slowly raise the pedal with your foot. Some people do this because they are embarrassed about the thump sound when releasing the toilet pedal. Doug

From Thetford FAQ section.

Water constantly runs or drips into my toilet's bowl. What should I do?
Within about 10 seconds after flushing the bowl will normally fill from 1-2 inches to provide a “water barrier.”

If the bowl continues to fill with water, the water valve is leaking and should be replaced.

When I replaced my Tetford with a Dometic.
I added a standard cut off valve... 1: made the job way easier since I needed to extend the line around a corner and the valve (1/2" IPT to 3/8 Compression) took one end of a flexible Toilet Connection hose which is designed to connect to it and the toilet's 1/2 INch IPT connection.. Turned a multi-trip to hardware store for another elbow job to about 2 minutes.

wa8yxm wrote:
When I replaced my Tetford with a Dometic.
I added a standard cut off valve... 1: made the job way easier since I needed to extend the line around a corner and the valve (1/2" IPT to 3/8 Compression) took one end of a flexible Toilet Connection hose which is designed to connect to it and the toilet's 1/2 INch IPT connection.. Turned a multi-trip to hardware store for another elbow job to about 2 minutes.

+1 I did this also, using the 310 about a year I'll never have a Tetford again, night and day difference, the 310 actually flushes!

slide your foot off and let the ball snap back.