Houston residents under heat wave still without power after Hurricane Beryl

July 13 (UPI) -- Nearly 700,000 electric customers in Houston were still without power Saturday, and most of them aren't expected to be back online until next week.

Of those, nearly 590,000 have service with Houston's main utility, CenterPoint Energy, according to Poweroutage.us . About 2.26 million CenterPoint customers initially didn't have electricity following Hurricane Beryl's devastating path through Texas on Monday, which killed at least 10 people in the Lone Star State.

CenterPoint serves 2.6 million in the state.

CenterPoint said it is rushing to repair the damage to the region's power grid but estimated about 500,000 customers will not get their power back until sometime next week.

Besides residential customers, the outages have affected vital infrastructure such as hospitals, assisted living facilities and water treatment plants.

Boil alerts are in place for eight counties in the Houston and Galveston areas, and distribution centers are handing out bottled water to people in need.

Texans, meanwhile, have been suffering without cooling under a heatwave, with temperatures peaking in the low 90s over the past week . The high temperatures are expected to persist into next week.

Many people have expressed frustration with CenterPoint over what they feel was a lack of preparation for Beryl.

The utility responded to customer complaints that its outage map showed areas without power as being restored.

According to CenterPoint, those residents may be experiencing a "nested outage," meaning power was restored to the equipment servicing the area, but some homes might still be without power due to a localized issue such as a damaged transformer or a fallen tree on a service line.

Texas Lt. Gov. Dan Patrick told CNN that Gov. Gregg Abbot requested an investigation into how CenterPoint and other utilities responded to the storm.

"I'm sure we will find that there are things they could have done better," Patrick said.

CenterPoint CEO Jason Wells told the Houston Chronicle he was proud of the company's efforts but acknowledged it could have responded better.

"I think we could do a better job of communicating expectations with our customers, and I personally own that," Wells said.

CenterPoint restored power to roughly 1.1 million within 48 hours of the storms' passing. Wells said.

CenterPoint initially mobilized about 3,000 contractors in anticipation of the storm, believing it would stay west of Houston, but the utility called about 7,000 more as the storm appeared ready to hit the city directly.

Shelters and cooling centers , meanwhile, have popped up in the greater Houston area for residents to escape their sweltering homes.

Houston Public Libraries, Harris County Precinct 4 and local YMCA centers all have opened their doors to allow residents the chance to escape the heat.

Additionally, the Houston Food Bank is supporting dozens of food distribution sites and shelters in the area.