Like gold and oil, water is a commodity - and it happens to be rather scarce. About 70% of the earth's surface is covered in water, but 97% of it is saltwater, which is unfit for human use. Saltwater cannot be used for drinking, crop irrigation or most industrial uses.

The City of Cape Town is set to gain millions of rands as its residents fail to adhere to water restrictions.

Ratepayers have been billed for more than R33-million in penalty fees for not complying with the restrictions in November and December.
Most of South Africa's metros have imposed water restrictions because of the drought.
The City of Cape Town applied level three water restrictions on November 1, meaning residents had to reduce their water usage by 30% or pay R23.54 a kilolitre if they used more than 10.5kl of water a month. Normal rate is R18.40 for residents who adhere to the restrictions.
City spokesman Priya Reddy said the city had billed residents an extra R1.51-million for November and R31.7-million in December.
Reddy said: "It also needs to be highlighted that the billed over-recovery is because the city has not achieved the water savings targets, as some consumers are not reducing their consumption in line with level-three water restrictions, preferring rather to pay the higher rates."
She said this indicated that many residents were still using potable water for watering gardens and filling pools.
"As such, the city will shortly be placing more stringent restrictions on these users," she said.
Reddy said the city had added 20 new recruits from the Expanded Public Works Programme to inspect water usage .
"Since the implementation of water restrictions, 383 notices of contraventions and 225 notices to appear in court have been issued."