HARRISBURG — Several tests of western Pennsylvania river water prompted by fears of contamination from the state’s rapidly growing natural gas drilling industry didn’t turn up elevated or harmful levels of radioactivity or other pollutants not routinely monitored, a private water utility said Monday.

The Pennsylvania American Water Co. said its tests showed that its water quality complies with federal and states standards.

Water for one set of tests was drawn from Pennsylvania American’s intakes along the Allegheny, Clarion and Monongahela rivers and Two Lick Creek, which serve the cities of Pittsburgh, Clarion, Kittanning and Indiana. In addition, Pennsylvania American said it found the same result after testing treated drinking water at three plants in late March.

State regulators have previously said that tests from samples they collected in November through February of water downriver from western Pennsylvania treatment plants raised no red flags for radioactivity. The treatment plants have been handling wastewater from drilling in the vast Marcellus Shale natural gas reservoir — a practice that is scheduled to end this week because of concerns over how it could affect drinking water.

Since the beginning of 2008, more than 3,000 Marcellus Shale wells have been drilled in Pennsylvania, raising fears of river contamination in part because ill-equipped riverside treatment plants were used to get rid of millions of barrels of ultra-salty, chemically tainted wastewater that gushed annually from the gas wells.

Pennsylvania American spokeswoman Josephine Posti said Monday that the utility did not have test results for the same contaminants to compare from 2009 or 2010, because the testing is done on a three-year cycle as required by state regulators. Tests in 2008 recorded no elevated or harmful levels, and neither did a test for uranium in the Clarion River in January, Posti said.