Updated — Friday, October 20, 5:43 p.m.: Construction starts Monday, October 23.

The Region of York recently completed a pilot project to rehabilitate sections of the York Durham Sewage System under 16th Avenue (Regional Road 74) in the City of Markham. During the pilot project, inspectors identified structural issues that require the Region to fully rehabilitate the sanitary sewer

• under 16th Avenue between Ninth Line and west of Mingay Avenue.

In “late May” (perhaps as early as Tuesday, May 22), contractors start installing a sewage bypass. They start fully rehabilitating the sewer “in July” (perhaps as early as Tuesday, July 4).

Crews mostly work Mondays to Fridays from about 7 a.m. until 7 p.m. However to complete the project as quickly as possible, they may also occasionally work overnight and weekends.

All lanes of traffic on 16th Avenue remain open during most of the construction period. However, York Region Transit passengers aboard buses along these routes can also expect detours or delays:

• 16 16th Avenue;
• 41 Markham local;
• 201 Markham GO shuttle;
• 301 Markham express; and
• 410 Markham high-school special via Carlton.

Sewer construction for the first phase of the project on 16th Avenue between Ninth Line and west of Williamson Road and the resulting YRT service changes continue “until August 2018”, meaning as late as August 31, 2018. Construction on the entire project continues “until summer 2019”, meaning as late as until September 30, 2019.