Abstract: A canine lavatory of modular construction for effective toilet training and continued use. A suitable site is selected and the dog is trained to relieve itself at-the site (typical training for a dog) and the lavatory enclosure is gradually built therearound after the dog has become enured to use the particular site. The lavatory comprises an enclosure with an open, readily accessible entrance having a flushing activating member for automatic activation by the entrance of the dog within the enclosure. The lavatory further comprises flushing and gravity dependent drainage systems. The flushing mechanism is adapted to be activated to fill to level and then to automatically trip flush. The filling and flush trip are adjustably timed according to dog habit and need. With the timed fill and self flush, the water fill system is completely purged of above-ground residual water to prevent freezing in an outdoor facility.