Believe it or not, November 19 is World Toilet Day, an annual event hosted by the World Toilet Organization since 2001 to raise awareness for proper sanitation world-wide.

From outhouses to water closets, humans devising creative ways to relieve themselves of nature's call can be traced back at least as far as 3,000 B.C., when Scottish settlements featured stone huts equipped with drains extending from recesses in their walls. Later, around 1,700 B.C., the Greeks built definite latrines featuring large, earthenware pans connected to a water supply that ran through terra-cotta pipes. And while ancient Rome had communal lavatories, medieval England castles had garderobes, and royalty had private privies with scented herbs and cushioned commodes.

In 1596, England leapt into modern sanitation when Queen Elizabeth I installed a new kind of water closet in her palace at Richmond: a raised cistern with a small pipe down which water ran when released by a valve. But it took another 200 years before Alexander Cummings developed the S-shaped pipe underneath the basin to keep out foul odors.

The flushable toilet went mainstream in the 1880s when England's Prince Edward hired a prominent London plumber named Thomas Crapper (yes, really) to construct lavatories in several Royal palaces. While Crapper patented a number of bathroom-related inventions, he did not—as is often believed—actually invent the modern toilet. It wasn't until the 20th century that bathroom technology really advanced with the invention of flushable valves, water tanks that rest on top of the bowl rather than above, and toilet paper rolls.

While these may seem like minor improvements, they moved bathroom fixtures from a luxury to a necessity, at least to those fortunate enough with access to proper sanitation. Around the world, 2.5 billion people still do not have access to proper sanitation, which endangers their health and the quality of their water and food.

Toilets are still being perfected, and the emphasis today is on efficiency. Toilets are by far the main source of water use in the home, accounting for nearly 30 percent of an average home's indoor water consumption.  In 1994, Congress required common flush toilets to use only 1.6 gallons of water—less than half of what they'd consumed before. The new "low-flow" toilets left a lot of consumers dissatisfied, due to their inability to remove waste effectively and their tendency to clog. But companies and the federal government have worked to develop better models so that today not only are low flow toilets efficient, quiet, and durable, but new innovations like waterless urinals are making their way to the marketplace that save consumers and businesses money and conserve water for other needs.

Did you know that there is even a label that can help you buy a more efficient toilet? The EPA estimates that toilets with the WaterSense label can save about 4,000 gallons of water per year. A family of four that replaces their old toilets WaterSense-labeled models could save about $90 per year on their water utility bills, and $2,000 over the life of the toilet. Calculate how much your family could save.

Learn more about World Toilet Day. Also check out some tips for saving water, and the best practices for managing toilets and urinals at federal agencies. While you're at it, also check out how to cut down on your hot water use.