Heavy oil recovery processes have traditionally used "once through" steam generators (OTSG) to produce high pressure steam for injection into geological formations containing heavy oil. The heat given up by the condensing steam fluidizes the heavy oil and allows the oil/water mixture to be brought to the surface. The oil is recovered as product and the water, referred to as produced water, is de-oiled and treated for feedwater to the OTSG. The typical treatment method for produced water is warm or hot lime softening (WLS or HLS), filtration, and weak acid cation exchange (WAC). An alternative method of produced water treatment is vertical tube, falling film, vapour compression evaporation. This method: 1) eliminates physical-chemical produced water treatment; 2) results in lower life cycle costs; 3) does not produce any softener sludge for disposal; 4) minimizes the number and volume of waste streams requiring disposal; 5) requires fewer maintenance materials and less maintenance labour; 6) reduces the required amount of produced water de-oiling equipment; 7) dramatically increases OTSG feed water quality, improving OTSG reliability; and, 8) provides increased system availability and reliability. For steam assisted gravity drainage (SAGD) processes, which require 100% quality steam, it has the added advantage of producing water of sufficient quality for use in standard packaged boilers in lieu of OTSG. Packaged boilers are less expensive than OTSG, produce a much smaller liquid blowdown stream, and result in a boiler feed system which is 20% smaller than that of an OTSG.