The City of St. John's pleaded with residents to avoid showers and laundry on Friday morning as reservoir levels continued to fill following an industrial accident.

Four of the five pumps used at the regional water supply at Bay Bulls-Big Pond facility were operational Friday morning, but reservoir levels remained low enough for the city to appeal for low water consumption.

A welder was injured Thursday afternoon when he received an electrical shock by making contact with equipment.

The incident cut off the main power supply to the treatment plant in the south end of St. John's, rendering it unable to pump water to reservoirs around the region.

Mayor Dennis O'Keefe said Friday the city is investigating why the backup generators didn't then kick in, but that their first priority was getting the pumps working again.

"That was the main focus, to get everything restored, get the water back in the system," O'Keefe said, "and then look at what happened to the generators, and what caused the incident to happen in the first place."

He said the pumps have been restored, but water rationing was still in place Friday because the reservoirs needed to be topped up.

"Just be a little bit patient," the mayor said. "Use common sense and limit the use of water, and allow everything to refill, and everything will be back to normal, totally."

The mayor admits the city was ready to push the panic button Thursday night.

"The only water that we had was the water that was in the system in the pipes and in the reservoirs," O'Keefe said.

"What was in the system probably would have lasted five to six hours, and then we literally would have been without water."

The City of St. John's made an unprecedented directive on Thursday, urging residents — as well as those in the neighbouring communities of Mount Pearl, Paradise, Conception Bay South and Portugal Cove-St. Philip's — to ration their use of water.

Commercial users were also asked to defer water use.

Municipal employees worked overnight to get the pumps back up and running, but water levels are still low on Friday.

The city urged people to continue to keep their water use to a minimum.