Absolutely.  Many of our customers have been using the Plant Booster system for watering their plants at their remote cottages where there is not "city" water supply.
Using any water source, such as a rain-barrel, or a bucket, the water level of which is above the plants that need to be watered, you can set the system up in exactly the same way as you would at home.
The Plant Booster device reacts to the weight of the plant it serves, and pinches or unpinches accordingly to let water through to maintain weight.  Water pressure is therefor effectively irrelevant.  The water pressure will only affect how fast the water will flow.
I have set up a system functioning perfectly well with only 1ft of water head (water level 1ft above the outlet of the tube into the plant)