Harrison residents are under a mandatory water conservation until further notice.

The township water authority issued an alert Wednesday that calls for residents to curb water use. Laundry, gardening and dish washing are not essential, they said.

The mandate comes after heavy storms rolled through the region Tuesday. Large trees were toppled throughout the township and numerous power lines were damaged.

Authority Manager Nicholas Colledge said utility problems are affecting the ability to run the water plant and distribution pumps throughout the system. He is working with the township, county and state agencies to correct the issues, he said.

Conservation is necessary to make sure there is an adequate supply of water for critical needs, such as drinking, fire safety and sanitation.

The state Public Utility Commission announced Wednesday that the heaviest impact of power outages remains in Allegheny County, which accounts for more than half of all reported outages.

“This was not a routine weather event. The intensity and scale of the damage — affecting not just electric systems but also roadways, cell towers and other infrastructure — requires an all-hands response,” said PUC Chairman Stephen M. DeFrank.

Commercial users are asked to reduce water use for nonessential operations.

The Authority will continue to monitor water levels closely and provide updates, Colledge said.

“We understand that these restrictions may be inconvenient, but they are necessary to ensure that we maintain adequate water supply levels,” said Chairman Mark Krumenacker.

Harrison residents are asked to report any suspected waterline breaks to 724-953-4984.