Eversource Energy failed to meet “standards of acceptable performance” in its preparation for Tropical Storm Isaias and its response after the Aug. 4 storm knocked out power to hundreds of thousands of customers, Connecticut regulators said Friday. 

The state Public Utilities Regulatory Authority said in its 109-page draft decision of an investigation into Eversource and United Illuminating that the Berlin-based utility had “communications systems failures” and fell short in coordination and communications with the towns.

Regulators said they will consider fines and penalties.

In contrast, PURA said UI was “markedly better” than Eversource in its preparation and response to the storm. Still, it said the utility was “underwhelming in specific instances” and did not fully meet “reasonable expectations” of PURA or its customers.

Eversource spokeswoman Caroline Pretyman said she recently received the draft decision and is reviewing it and will comment in more detail later.

“As we’ve said all along, we stand by our response to Tropical Storm Isaias,” she said. “We were well prepared for this storm even though the forecast changed drastically as the storm arrived — causing unprecedented damage in Connecticut.”

Eversource assembled the largest team of repair crews ever in Connecticut, Pretyman said.

Following comments from the utilities, PURA next month will issue its final decision that could be different from its draft findings.

About 1 million Connecticut customers lost power after Isaias for days, with many in the dark for nine days.

Marissa Paslick Gillett, PURA’s chairwoman, said in the aftermath of the storm that Eversource wrongly classified its strength in paperwork filed with the state. The utility told officials it prepared for a “level 4” event with no more than 375,000 outages.

United Illuminating prepared for a “level 3” storm that could include as many as 650,000 outages, she said.

PURA announced Aug. 6 it was responding to Gov. Ned Lamont’s call for an investigation into whether the utilities were adequately prepared and have the resources to respond to “significant weather events.”

Even before regulators began their probe, Gillett said a “significant failure in communication” left 800,000 Eversource customers “without even a clear way to report an outage.”

“There are disturbing reports emerging about the coordination, or lack thereof, between our electric utilities and the communities which they serve. This is simply unacceptable,” she said.

Eversource acknowledged communications problems, but said crews restored electricity faster after Isaias than from the more damaging Hurricane Irene in 2011 and Superstorm Sandy the following year.