Helicopter buckets and fixed tanks can be equipped with foam injection systems.   These systems inject foam concentrate into the water at a desired volume.

Foam injection units and reservoirs can be located either in the aircraft or inside the bucket or tank with controls located in the cockpit.

While most systems inject the foam inside the tank or bucket, some inject the foam into the flow of water as it exits the bucket.   This may reduce contamination of the bucket.

Reservoir size will usually allow for 5-10 drops before refilling.   Mixed ratios may vary up to 1% with the suggested ratio being 0.5%.   The injection system design must allow for even distribution and mix of foam concentrate.