In some situations, water can also be moved without using a pump. In this case we make use of siphon systems, where gravity acts as the power source. However, this does require a height difference between the beginning and the end of the pipeline. To activate a siphon, the pipe must be completely filled with water. A vacuum system is used for this purpose. The parameters with which we can calculate a siphon are:

- Height difference
- Conductor diameter and length
- Conduction resistance

The above chart shows the capacity of a randomized siphon, by varying the height difference and the pipe diameter.