Free RV manual
How an RV Toilet Works
How to flush, what paper to use and how to keep the black tank from clogging or smelling.
How it flushes
Most RV toilets drop straight into the black tank below. Press the pedal or handle and a flap opens with a rinse of water. Some have a second pedal that adds water to the bowl without opening the flap.
Always add water to the bowl before you use it. A dry bowl lets waste stick and lets smell come up from the tank.
What goes in
- Use RV toilet paper or any paper sold as septic safe.
- Never flush wipes, even ones sold as flushable. They do not break down and they clog the tank.
- Nothing else goes in. No food, no paper towels and nothing from the sink.
- Use plenty of water with each flush. Water is what moves waste to the dump valve.
Keeping it clean
Put a few gallons of water and a tank treatment into the black tank after you dump it. This keeps solids from drying on the bottom.
Keep the black valve closed at a site with sewer, even on a long stay. If it stays open the liquid drains out and the solids stay behind in a pile. Dump when it is at least two thirds full.
When it smells
Check that the bowl seal holds water. A dry or worn seal lets the tank smell in. Rub the seal with a little plumber's grease or a seal conditioner.
Check the vent on the roof. It must be clear so gas leaves the tank. On a windy day, a vent cap that pulls air up helps.
When to call a shop
Call a shop if the flap will not close, the toilet leaks at the floor, or the tank sensor says full right after you dump. A stuck clog may need a tank flush service.
The maker's own manuals
These guides cover how most RVs work. Your own rig may differ, so check the manual for your make and model.
- Thetford and Norcold · Norcold fridges and Thetford toilets
- Dometic · Fridges, air conditioners and awnings
- Every maker we link to