Expect Simpson Avenue to be closed in both directions as work starts to replace the 100-year-old water lines that will shut down entire blocks — one block at a time — to through traffic and block access to driveways and businesses starting Monday.

Hoquiam City Administrator Brian Shay made the announcement Wednesday afternoon.

“The goal of this project is to improve water quality, eliminate leaks, lessen the chance of breaks and unexpected interruptions in service and decrease long-term maintenance costs,” he said.

The work will begin Monday at Emerson Avenue. Several blocks will be upgraded between there and Eighth Avenue, then move east to between 22nd and 23rd streets, between Ontario and 27th Street, 27th Street to 28th Street, and 28th Street to 30th Street. Additional crossings will also be addressed on 23rd Street and Myrtle Street.

Shay said stormwater drainage will be included in the project on Ontario Street between Simpson and Sumner avenues, a notorious trouble spot for standing water for many years.

Shay said the contractor, Ronglin’s Inc., will identify and post road detours in each section of construction. Construction is expected to take about five months to complete. Work hours will be between 7:30 a.m. and 4:30 p.m. weekdays, except holidays, and some Saturday work may be required. There will also be some impact to water services in the area surrounding the construction, though Shay said most of these brief disruptions in service will happen at night.