Water from Lake Ontario enters the intake mouth located in 18 metres of water about 1,615 m from shore. It reaches the plant through a 3,275 millimetre (mm) diameter concrete lined tunnel, in rock, approximately 30 metres below the lake bed.

• Screening
  Three 1.5 wide by 8.5 metre high travelling screens remove the larger particles of suspended debris from the raw water.

• Raw Water Pumps
  Three 136 and two 205 ML/d pumps lift the water from the lake to the mixing chambers so that it will flow by gravity through the rest of the plant.

• Pre-chlorination and Application of Alum
  The water is pre-chlorinated at the raw water suction well, and alum is added at the entrance to the mixing chambers to aid in the settling process. The alum forms a jelly-like substance which joins together with impurities forming large particles called floc. Zebra mussel control facilities are installed for pre-chlorination at the intake mouth, during zebra mussel season.

• Mixing
  Six high speed mixers ensure that the alum is completely mixed with the water.

• Flocculation
  Twenty-four sets of slowly moving paddles and two mechanical mixers in three raw water modules gently agitate the water and alum mixture. This provides the best conditions for formation of floc.

• Settling
  After flocculation, the water passes very slowly through the three settling basins during which time the floc settles to the bottom carrying with it most of the suspended impurities. The cleaner water at the top of the settling tanks proceeds to the filters.

• Filtration
  Settled water passes through the 18 dual media filters. The filter media consists of 0.457 metres of graded gravel with the largest size on the bottom, covered by 0.300 metres of sand and 0.450 metres of anthracite filter media. In the filters the remaining suspended impurities, as well as some bacteria and other microorganisms, are removed.

• Disinfection and Fluoridation
  Following filtration, the water is post-chlorinated to completely destroy harmful bacteria and is then fluoridated to 1.2 milligrams per litre. When high levels of bacteria are present, the chlorine dosage may be increased through a process called "super-chlorination" and the resulting chlorine content is reduced by addition of sulphur dioxide.

• Ammoniation
  Just before being pumped to the system, the water is ammoniated so that the residual chlorine is in the combined state and will last much longer in the distribution system.

• High Lift Pumps
  The filtered, chlorinated and fluoridated water is now pumped into the distribution system, to storage and to the consumer.

• Metering
  As the water leaves the plant, the flow is accurately measured to indicate the plant output and for billing purposes.