> For the complete documentation index, see [llms.txt](https://help.waterwatch.io/3.0.1/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.waterwatch.io/3.0.1/support/untitled.md).

# Valid Sensor Ranges

How far/close can my sensor measure

Waterwatch sensors have limitations in the measurement distance.  If the sensor is too close or too far from the surface, the sensor is not able to record a valid measurement. Different types of sensors usually have their own minimum and maximum ranges.

| **Sensor model**              | **Min distance from surface** | **Max distance from surface** |
| ----------------------------- | ----------------------------- | ----------------------------- |
| *LS1*                         | 0.3 metre                     | 5 metres                      |
| <p><em>LS1-10M</em><br></p>   | 0.5 metre                     | 10 metres                     |
| <p><em>LS1-P</em><br></p>     | 0.1 metre                     | 10 metres                     |
| <p><em>LS1-P-20M</em><br></p> | 0.1 metre                     | 20 metres                     |
| <p><em>LS1-R</em><br></p>     | 0.2 metre                     | 7 metres                      |
| <p><em>T35</em><br></p>       | 0.2 metre                     | 3.5 metres                    |

Please note that the distance is calculated from the sensor module (not the device) to the surface. For example, for ***T35*** sensors, the sensor module is at the bottom of the sensor; for ***LS1-P*** sensors, the sensor module is the cylindar metal piece, attaching to the end of the cable.