SAN ANTONIO -- In a remote south side lab, SAWS lab technicians test hundreds of vials of drinking water. Carefully-prepared test tubes are placed on a rack next to a hulking machine. A thin, needle-like appendage sucks it up into a glowing chamber, where plasma heats it to a temperature almost double that of the sun.
The water is vaporized into its individual elements, but in this case they're most interested in one: lead.
"The regulatory limit for that is 15 parts per billion," SAWS Chief Operating Officer Steve Clause said. "We typically get 0.002 parts per billion, extremely low levels overall."
The powerful neurotoxin has invaded the water supply of Flint, Michigan, causing faucets to belch out yellow water, and causing many around the country to worry about their own drinking water.
Clause says San Antonians will likely never see that happen; that's because the city, and many smaller towns around it, saw this coming decades ago.
"Back in the 90's we made a big push to remove all lead pipes from our system," Clause said.
As a result, most of the water infrastructure in South Texas is made from more modern PVC or galvanized steel, materials that have fewer and less dangerous contaminants.
Clause also says the hard water that leaves annoying stains on dishes makes San Antonio's nine water sources among the safest around.
"It builds up calcium on dishwashers and that sort of thing periodically. That's buffering," Clause said. "That keeps the water from trying to pull minerals and metals out of pipelines."
The system that keeps San Antonio water mostly lead-free is the same used in many of the smaller, rural towns surrounding it. Towns like Somerset, Selma, Poteet, and Elmendorf ship their water samples to the Pollution Control Services, one of a handful of private labs certified to do lead and copper testing by the Texas Commission on Environmental Quality.
Owner Chuck Wallgren says that water is all tested under the same strict standards that apply to SAWS.
The biggest risk, according to Wallgren, comes from outdated or poorly-made faucets, which often use brass components that can leak copper and lead. He says those worried about contamination should flush their faucets periodically by running a liter or so into the sink.
Despite that risk, local experts agree that a Flint-like disaster would require an extreme and unlikely lack of oversight.
"The reality is we're not going to see that type of a problem in San Antonio," Clause said.