From Toilet to Tap

From Toilet to Tap

Facility uses sophisticated technology to transform wastewater into clean water.


3 - 12+


Engineering, Geography, Human Geography, Physical Geography, Physics, Social Studies, Economics

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Water often runs low in California. So, some people are trying new ways to get drinkable water. One new way involves turning sewage into tap water.

Sewage is waste water. It is flushed into sewers from our toilets. This may sound a little foul at first. However, the plan is working.

Shivaji Deshmukh helps lead a Groundwater Replenishment System (GWRS). It is part of the Orange County Water District, in California. The GWRS uses special filters to clean sewage water.

Deshmukh holds a cup of water. "A day ago, it was raw sewage," he says. Deshmukh then chugs down the water. It shows how much he believes in the project.

I got a tour of Deshmukh's facility. Inside, it is filled with stacks of plastic pipes. Right next to the GWRS is the Orange County Sanitation District (OCSD). Here, sewage from northwest Orange County is first treated.

Every day, OCSD sends water over to the GWRS. It goes through a .8 kilometer (.5 mile) long pipe.

Michael Gold was an official for OCSD. The water that gets there is smelly and dirty at first, he says. OCSD cleans up the smelly water a bit. Yet at this point it still is not good enough to drink.

Three Processes

The GWRS uses three methods to make water drinkable.

The first step gets rid of germs that would make people sick. It also gets rid of solid materials in the liquid. Liquid gets pushed through many fibers. These are filled with tiny, hollow tubes. Deshmukh compared it to drinking iced soda through a straw. The pollutants are like the ice. It is too big to fit through the straw. Powerful engines help push water through these filters.

Next, viruses, salts, and bits of medicines have to be taken out. This is done with reverse osmosis. This is when water is pushed through plastic sheets. Powerful engines help move it along. This separates more unwanted material from the water.

The final step involves ultraviolet (UV) lightbulbs. These bulbs are inside many steel tubes. The water passes by this light. This special kind of light can destroy leftover germs.

After this, minerals are added back to the water. Minerals help water taste better. They are also needed in our bodies.


Much of this water is then pumped 21 kilometers (13 miles) away to the city Anaheim. There, it is released into several lakes. It mixes with rainwater. Then it settles underground as groundwater.

In about six months, chlorine is added to the groundwater. This further cleans it of germs. Then, water is sent to Orange County. Now it can be used for drinking.

The Orange County Water District treats enough water for about 850,000 people each year. The GWRS also stops wastewater from being released into the ocean.

The idea of drinking old toilet water might sound gross. However, the success of GWRS changed California's thinking. There are plans to build more facilities like it.

Fast Fact

Water Wisdom
Before the Groundwater Replenishment System began processing treated sewer water in January 2008, the Orange County Water District's Water Factory 21 was the first facility to use reverse osmosis to make municipal sewer water into purified drinking water.

Media Credits

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Stuart Thornton
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
National Geographic Society
Last Updated

April 29, 2024

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