Sunoco Pipeline LP has suspended installation of its contentious Mariner East 2 underground pipeline near Exton after about a dozen Chester County households complained that the water from their private wells was interrupted or had become cloudy.

The Newtown Square company put five families up in a local hotel Wednesday and provided bottled water to a dozen families near Township Line Road in West Whiteland and Uwchlan Townships, Sunoco spokesman Jeff Shields said. Two to three of the families remained in hotels, he said Friday evening.

"We have notified the Pennsylvania Department of Environmental Protection, the townships, and all appropriate agencies, and will do everything in our power to minimize the impacts to homeowners," Shields said.

State environmental regulators say there is no confirmed impact on any public water supplies. "DEP has been notified of potential private water-supply impacts and is currently investigating," said Neil Shader, a department spokesman.

Sunoco has tested 23 water wells in the area where its contractor is conducting horizontal-drilling operations about 190 feet below the surface to install the Mariner East 2 pipeline.

"Drilling has been suspended as we await test results, which will help determine whether the well problems are related to drilling and, if so, help us resolve the issues," Shields said.

The problems were first reported to authorities Monday, he said.

The drilling involved the second of three pipelines through which Sunoco is delivering natural-gas liquids such as propane from the Western Pennsylvania shale fields to its terminal in Marcus Hook. Political, business, and labor leaders have touted the $2.5 billion Mariner East project as a major economic boost, but it has also generated fierce resistance from some nearby property owners and environmental activists opposed to fossil-fuel development.

Local officials suspect that nontoxic bentonite clay used as a lubricant during the horizontal-drilling process may have migrated into private wells. Bentonite drilling mud is the same material used in cat litter.

In a September report citing "technical deficiencies" in Sunoco's pipeline application, DEP singled out geologic formations near Exton and East Whiteland Township as presenting an "additional risk" of contamination or "inadvertent returns" during horizontal drilling. It asked Sunoco to provide "a detailed assessment of measures to reduce the risk of drilling" in the area.

Sunoco, in its February response to DEP, said it had worked with the public water supplier in the area, Aqua Pennsylvania, to step up groundwater-monitoring efforts, including the installation of a monitoring well near Aqua's two Hillside water wells, which are about 300 feet from the pipeline route.

Donna Alston, a spokeswoman for the Bryn Mawr water company, said Aqua had been monitoring water quality on its system during the pipeline construction. "We have not seen any impact on our wells," she said Friday.