Water

1. Drinking

2. Washing

3. cleaning

4. growing (plants)

5. ( OK, that's all I got )

are there 6 more you can't put into one of the above?

5. Pseudoscience ICE fuel (through use of high current and electrolysis)

6. Pseudoscience cold fusion fuel (through use of high voltage and averaging multimeter)

7. Sanitation

Technically speaking 5, 6 and 7 are fundamentally the same.

Does making ice count as uncommon? If not

8. Ice

Jack - A former lab guy

okay here's a couple more:

5. cutting material with water jet

6. "chinese" water torture

7. security moat (ya, ya, every castle wants one...)

8. power source (oh the work of getting out the hydrogen to burn)

9. hmmm... I ran out of ideas! no wait, splashed on the wrists and back of the neck, water will revive the fainted.

10. baptism

There could be a geographical component like"firefighting in Antarctica"

Good point..

we forgot the making of rare tea: uncommon boiling water extraction

The ten that don't spring immediately to mind.....