The Lakeshore Water Treatment Plant (LWTP) is a surface water supply and treatment facility located at 2155 25th Sideroad in Innisfil. The plant was first commissioned in 1996 and expanded to 26 MLD in 2006. In 2011, an Environmental Assessment (EA) was undertaken to increase capacity of the LWTP to 11 MLD by a multi-phase expansion. In 2014, a new recommended solution was identified in an addendum to the 2011 EA which concluded a new intake in Lake Simcoe was required.

As per the 2011 EA and the 2014 EA addendum, the below three-phase approach was identified:

• Phase 3A - expansion to 38 MLD at 20°C (or 30 ML/day at 3°C), 45MLD gross raw water capacity
• Phase 3B - expansion to 55 MLD at 20°C (or 44 ML/day at 3°C), 66 MLD gross raw water capacity
• Phase 3C - expansion to 85 MLD at 20°C (or 68 ML/day at 3°C),102 MLD gross raw water capacity

In 2018, the LWTP and Low Lift Pump Station (LLPS) were upgraded as part of the Phase 3A expansion. In 2022, RV. Anderson Associates Limited was retained to complete the investigative studied and preliminary design for the new second intake as recommended by the 2014 EA Addendum.

The 2023 Master Servicing Plan (MSP) update noted that the Phase 3C expansion to the Lakeshore Water Treatment Plant (LWTP) was sufficient to meet the demands up to 2051. However, due to significant growth projections beyond the year 2051, the Phase 3B Intake Preliminary Design Report has confirmed a peak capacity of 130 MLD (gross water capacity) for the second intake.

InnServices released RFP P-25-46 for the Detailed Design, Contract Administration and Construction Inspection of the LWTP Phase 3B Expansion and Upgrades on January 2, 2026 and it closed on February 20, 2026.