Hi Morten,
We do not recommend all our sensor to become in direct contact with any kind of liquid substance or corrosive gases which would damage the gel and cause the sensor to become out of specification.
However, our products are used in washing machine applications, which would expose the gel to a humid environment. In these applications, the device is located at the top of a measurement tube - so water level is indirectly measured through the water pushing a trapped air column up to the sensor. As you can see in the following application notes, the sensor does not have a direct contact with water, but is separated by the air column.
http://www.freescale.com/files/sensors/doc/app_note/AN1950.pdf
AN1950: Water Level Monitoring
AN1516: Liquid Level Control Using a Pressure Sensor
AN3728: Media Compatibility for IPS PRT Pressure Sensors
Our sensors come in differential, gauge or absolute configuration and the sensors that can handle up t 1 bar are the MPXx2200 or MPXx2202.
Hope it helps!
Darío