After using the toilet we normally wash our hands. Before taking a shower, we often use the toilet. Before washing, we commonly allow the hot water to run in the sink or tub until it warms up, producing unnecessary waste.

This design uses a temperature controlled valve to direct cold water from the hot line to fill the toilet tank after flushing. When the water heats to 85 degrees Fahrenheit, the valve switches over to the cold pipe and completes filling the toilet tank.

Water previously wasted warming the hot tap is instead routed to fill the toilet tank.

Check valves (one-directional flow valves) prevent water routing through the Hot Water Toilet Primer between hot and cold.

Options include:

1) the ability to force cold water use when the hot water priming function is undesirable

2) an external temperature sensor to place at the sink or tub nearest (upstream or downstream) the toilet. This avoids wasting hot water on the pipe between the Hot Water Toilet Primer and the sink or tub