At what was already the umpteenth Democratic presidential debate – March 6 in Flint, Michigan – Hillary Clinton and Sen. Bernie Sanders both vowed to use government muscle to end the problem of lead in water. Clinton called for an “absolute commitment to getting rid of lead wherever it is…within five years,” while Sanders promised to “rebuild water systems that are unsafe for drinking.”

Unfortunately, such grandiose promises would require a cost-prohibitive commitment that would still leave a large risk of water contamination.

Fitch Ratings Agency and the American Water Works Association recently offered estimates that mandating municipalities nationwide to remove and replace lead pipes would cost somewhere in the range of $30 to $50 billion. Even if this gargantuan task could be realized and not come in over budget, such efforts could take more than a decade. Removal efforts would prove complicated, Vox’s Libby Nelson explains, because “many cities simply have no idea how many lead service lines they have or where they might be.”

Thus, for the whole of this indefinite time period, plus additional delays characteristic of public-sector infrastructure projects, the gross injustice of children in low-income areas drinking contaminated water would continue. And even after this multidecadal stretch, the water supply would still be prone to the snafus we have observed in Charleston, West Virginia and Durango, Colorado. In those cases, point-source pollution ensured a contaminated end product, regardless whether the pipes were made of lead.

Many residents living with lead-tainted water have already shown their unwillingness to wait for a structural fix. A number of households and restaurants in Flint have already installed reverse-osmosis filtration systems, which can eliminate contaminants like lead that charcoal-based filters cannot. Some groups are buying similarly-effective Berkey filtration devices in bulk and donating them to distressed Flint residents.

In places where water contamination is within acceptable limits, tap water from public utilities will remain a small fraction of the cost of these filters. Tap water typically sets customers back a fraction of a cent per gallon, compared to about 1.5 cents for Berkey filters and 30-60 cents for reverse-osmosis filtration. For these areas, continued reliance on tap water is a no-brainer. In his indictment of the filtration industry, The Daily Beast’s Michael Schulson quips that “Rome’s aqueduct builders” are “rolling with envy” due to our society’s “sophisticated, reliable and sanitary” water system.

But for households perched at the end of 6.1 million lead-piped service lines, this is not so. For these at-risk households, waiting years for pipes to be replaced means risking diminished IQ, serious damage to organs and other unacceptable maladies.

Instead of a national public-works endeavor – which would be fragile to political interference, federal-local coordination issues and implementation delays – the federal government should create a voucher system for the purchase of at-home filtration devices. Shopping around for the lowest-priced systems could be encouraged by allowing households to keep the unused portion of the voucher to cover other needs.

Few households currently purchase these systems, as our largely safe tap-water systems discourage families from seeking out filtration systems more sophisticated than, say, Britas. But with a deeper consumer market, we could see downward pressure on prices that makes household systems far less expensive relative to tap-water provision.

Filtration vouchers, of course, are no panacea. Opponents of this approach rightfully point out that shoppers may make ill-informed purchasing decisions and may be duped by deceptive marketing. Examples are rife of companies overselling the benefits of expensive filtration systems. But these market imperfections need to be compared to public-sector failures in water safety.

We’ve already seen how Flint officials reneged on Detroit Water and Sewage Department’s (DWSD) offer to slash water rates by 50 percent and instead relied on toxic Flint River water while waiting for a new pipeline to be built. As Reason’s Shikha Dalmia has documented, Flint authorities went for a more dangerous water option out of fear that another long-term contract with the DWSD would eliminate the public-works jobs that come with a new pipeline.

Decisions by public-sector officials often are ill-informed and designed to maximize stimulus or public-works dollars, rather than human flourishing. It would be better to offer victims of municipalities’ disastrous water policies a practical way out of lead poisoning and premature death.

Vouchers may not be perfect, but they sure beat a prolonged pipe-removal effort prone to municipal authorities’ inevitable missteps. With a market solution, Clinton’s call to get “rid of lead wherever it is” could be made more than a pipe dream.