Aging water treatment systems, failing pipes and a slew of unregulated contaminants threaten to undermine water quality in U.S. cities of all sizes.

Why it matters: There's arguably nothing more important to human survival than access to clean drinking water.

Still, with only a handful of exceptions, "water systems aren't designed to focus on health, they're focused on cost-containment," says Seth Siegel, whose book "Troubled Water," released this month, examines the precarious state of water infrastructure in the U.S.

The big picture: Whatever goes down the sink, shower, washing machine and toilet is transferred to one of about 14,000 U.S. wastewater treatment plants. While those plants are good at neutralizing sewage microorganisms that can make people sick or pollute waterways, they can miss chemicals that are linked with our changing lifestyles.

The biggest change since most treatment plants were designed? The explosion of pharmaceutical use by Americans, Siegel told me during an interview in Axios' office.

About 60% of American adults take at least one prescription pill every day, per the National Center for Health Statistics. Residue from those pills travels to treatment plants and waterways.

Water testing often doesn't accurately reflect the risks of tap water, and testing processes can be manipulated to show passing results.

"There is evidence that we are being exposed to lots of pharmaceutical products at low levels — sub-therapeutic levels. ... We don't know who is drinking it or in what combinations or amounts."

— Luke Iwanowicz, U.S. Geological Survey research biologist, in "Troubled Water"

Meanwhile: City leaders are typically reluctant to raise water rates to pay for plant and pipe upgrades out of fear that residents will see it as an increased tax.

At the same time, though, bottled water sales are at record highs, and 90% of bottled-water consumers cite safety or quality for the reason. That suggests people are willing to pay more for clean water, Siegel writes.

What's next: Siegel argues for consolidation of the number of water utilities — there are currently 51,535 drinking water utilities in the U.S., translating to 16 for every county. Los Angeles County alone has 200.

Such a large number of utilities impedes the adoption of new technologies, the replacement of failing pipes and the retention of trained engineers, he says.

impedes the adoption of new technologies, the replacement of failing pipes and the retention of trained engineers, he says. Utility management should be decoupled from municipal politics, he argues. With mayors valuing cost control over water quality control, they will continue to defer maintenance and needed infrastructure upgrades.

should be decoupled from municipal politics, he argues. With mayors valuing cost control over water quality control, they will continue to defer maintenance and needed infrastructure upgrades. Those upgrades will soon be unavoidable. There are 1.1 million miles of old water mains carry drinking water across the country, and at least 240,000 of them break every year.

The bottom line: The high levels of public trust local leaders enjoy will likely evaporate when residents become more aware of the health risks in their tap water, Siegel says.

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