The Nelson Mandela Bay metro braces for week-long water outages after two major electricity failures and a substation explosion.

A large substation in Nelson Mandela Bay's industrial development zone exploded on Saturday night, causing more widespread water outages in a metro that has been hard-hit by ongoing water shortages and drought.

The explosion led to the third major electricity blackout to hit the water supply line in four days.

Authorities said there were signs of forced entry at the substation.

Water supply to Nelson Mandela Bay has been in crisis for some time with supply dams now having only 6.97% of water left, or around 19,114 megalitres.

Nelson Mandela Bay is one of the country's widest metros, making water crisis management very difficult. Its water supply is mainly from the Nooitgedacht Water Scheme, which requires it to pump water from its eastern side to its western side, but electricity failures make this impossible.

"This has seriously affected our ability to stabilise the system, which simply can't meet demand," Nelson Mandela Bay Executive...