Water circulating units have been installed at Lake Oneida Dam in Oakland Township.

Pennsylvania American Water began monthly water quality sampling by boat this week on the Lake Oneida and Thorn Run reservoirs. The water utility said this is to help ensure safe, high-quality and reliable drinking water for customers in Butler County.

The monitoring program, according to Pennsylvania American Water, allows the utility to “better understand” changing conditions in the reservoirs, help operators adjust treatment processes and maintain water quality for customers.

Pennsylvania American Water uses boat-based sampling to check overall reservoir health. This includes monitoring water quality indicators like temperature, pH, dissolved oxygen and chlorophyll, along with laboratory analysis to evaluate algae levels.

More than 20,000 customer connections are served by these water sources, according to Pennsylvania American Water. The Lake Oneida and Thorn Run reservoirs supply water to customers in the City of Butler; Butler, Center, Clinton, Connoquenessing, Donegal, Forward, Franklin, Jackson, Jefferson, Lancaster, Oakland, Penn and Summit townships; and Connoquenessing, East Butler and Saxonburg boroughs.

“Along with sampling, the company uses solar-powered mixers in both reservoirs to improve water quality. These mixers prevent algae growth by providing continuous circulation within the reservoirs,” a news release from Pennsylvania American Water said.

After past community concerns over taste and odor, the state Department of Environmental Protection has previously said algae growth in Lake Oneida in Oakland Township does not impact the safety of drinking water. Growth is due to hot weather and elevated levels of nutrients, the company said. The algae — a microscopic plant — produces an odd, but harmless taste or odor.

The DEP said algae can affect water in terms of taste or odor, but treatment plants, like the one at Lake Oneida, have DEP-permitted processes and monitoring procedures in place to address surface water contaminants to ensure that public health is protected.

“Treatment at surface water plants includes processes such as coagulation, sedimentation, filtration and disinfection. These treatment processes are routinely monitored for parameters such as turbidity and disinfectant residual to ensure water meets the Safe Drinking Water Act and regulations’ maximum contaminant levels and standards. These results are reported to DEP monthly,” a DEP statement said.