When it comes to water, the City of Houston has a not-so-secret weapon in its municipal arsenal — the toilets and sinks of Dallas.

It's not as wretched as it sounds, actually. The water is treated in Dallas before it enters the Trinity River and flows to Lake Livingston, mixing with rain and groundwater before getting tested and pumped across the greater Houston area.

"The water is incredibly clean and nutrient-rich when it leaves the filtration plant," Alvin Wright, spokesperson for Houston's Public Works and Engineering Department says. "Naturally-occurring bacteria and minerals break down any other pollutants in the water as it flows from north Texas."

Each summer, though, the 250-mile water reclamation process is put to the test as water tables drop to their lowest annual levels. The 2011 drought added a new layer of concern.

"Just downstream from Dallas, the percentage of treated water in the Trinity is somewhere in the mid-90s during dry months like August," Glenn Clingenpeel, a senior manager with the Trinity River Authority, tells CultureMap. "This August it was close to 100 percent."

As the threat of drought continues and populations boom across the state, large urban centers like San Antonio are considering ways to repurpose wastewater closer to home.

According to a recent report, Fort Worth's water department is working on a wastewater reuse project that is limiting some of its water coming downstream to Houston.

Wright said the Houston Public Works Department has considered a variety of possible outcomes effecting the city's future water supply. As such, in 2011, the department secured permission from the Texas Commission on Environmental Quality (TCEQ) to recycle up to 60 percent of city’s wastewater. The new permission was only a precautionary measure, he said, and no new treatments plants have been planned.

"Public perception is always a little tricky when it comes to water reuse," Clingenpeel says. "Water recycling, though, never means 'toilet-to-tap.' We're a long way from that type of direct reuse, but there are many indirect methods that are highly effective.

"Sewage water was something local governments tried to get rid of decades ago The quality of treated water is so high now, it makes sense to reuse the water."