There is usually *no warranty* on a biodigester for a few practical reasons, not because it is a bad system:
- *It has no moving parts:* Unlike a machine, a biodigester is just a sealed tank, pipes, and bacteria. There is nothing mechanical to break down and warrant like a motor or pump.
- *It depends on how you use it:* If harsh chemicals, bleach, sanitary pads, plastics, or too much water enter the system, the bacteria die and gas production stops. A provider cannot warrant against misuse.
- *It is built underground:* Soil movement, tree roots, flooding, heavy vehicles driving over it, or poor drainage can crack or shift the tank. That is output depends on temperature, feeding, water levels, and bacterial activity. No one can guarantee an exact amount of gas every day