FREMONT, Neb. (AP) — Fremont officials are suggesting that residents boil their tap water or use bottled water until further notice.

City utilities manager Brian Newton said the notice follows a series of thunderstorms and lightning strikes late Wednesday and early Thursday that knocked out power to emergency backup generators to the water treatment facility. The power outage caused a brief loss of pressure, which could have led to contamination.

Newton says water test results are expected Friday, and he’s hoping they’ll show the water to be safe for consumption. The Fremont State Recreation Area is included, as the area uses city water.