Motorists are encountering some bumpy streets in Butler as Pennsylvania American Water is replacing the 80-year-old water mains along West Jefferson and West Cunningham streets.

The project that is expected to be done in early May, a spokesman said.

The line replacements, which include almost one mile of main water lines, will improve service reliability and increase water flow for firefighting.

Company spokesman Gary Lobaugh said the project in Butler amounts to about $960,000 and started in early April.

The company has said it expects to complete pipe replacement, service connection tie-ins, and “final paving restoration” by late summer.

Also causing traffic problems in the city is the shutdown of the bridge over Sullivan Run at the intersection of Jefferson and Cunningham streets.

That is a $2.2 million project by the state Department of Transportation to replace the bridge with a box culvert. The work is expected to shut the bridge down until mid-October.