Walls with water (pipes, drainage, etc.) in kitchens or bathrooms can significantly lower signal strength. Connecting devices through walls containing water lower signal quality, whereas connecting devices parallel to the same walls does not.

Where possible, avoid placing TMEs that need to communicate through walls containing water. An extra TME is needed in this case, placed in a clear line of sight to the next device.

Figures a) and b) below illustrate connections through walls containing water. In figure b), an extra TME is added to improve signal strength.
Conversely, figure c) illustrates a connection that runs through a wall parallel to the water installations (no extra TME required).