Michigan Gov. Rick Synder wants to replace every underground lead water service pipe in his state within two decades. In the process, his administration is giving a common, but risky lead pipe replacement practice another look.

Here’s the issue: State officials plan to give communities 20 years to replace an estimated 500,000-plus lead service lines in a state with the third-most lines in the U.S. The Synder administration is doing this hand-in-hand with a promised rule that Michigan’s “action level” for lead in drinking water would gradually drop to 10 parts per billion (ppb) by 2024. That would be stricter than even the federal threshold of 15 ppb, embedded in the EPA’s Lead and Copper Rule, which the governor has called “dumb and dangerous.”

Synder originally outlined his plan back in April 2016 as a mea culpa for his administration’s role in the Flint water crisis. By now, we all know how lead leached into Flint’s drinking water from old lead lines leaving residents to drink and bathe with bottled, and, later, filtered water. Public health experts also blame the switch to improperly treated Flint River water with a local outbreak of Legionnaires’ disease that killed 12.

Here’s the rub: Under the draft rules, utilities would fully replace all lead service lines at their expense, though the cost would be passed along to customers. A homeowner could decline to allow the replacement of the private portion of the pipe, which is typically between the house and sidewalk.

But that’s a shift from an earlier plan to prohibit partial replacement of lead lines. Eric Oswald, director of the Michigan’s Drinking Water and Municipal Assistance Division, had told the AP beforehand that "the ultimate goal here is to get lead out of the system" by pushing municipalities to replace the old lead pipes running from water mains to houses or else face "difficult" new operational rules including stricter sampling requirements.

Here’s the problem: Digging and jackhammering around lead pipe will naturally jiggle lose bits of rust and scale inside the pipe. Those lead-laden pieces will flake off into the tap water for a time.

That’s one part of the process that most would consider, at least an acute, short-term problem that could be dealt with through proper filtration inside the home.

However, there’s a much bigger chronic problem that results when the utility replaces half of the old lead service line with brand-new copper pipe.

Swapping one out for the other sounds like a reasonable “bit-by-bit” approach. But maybe not. Researchers have found that removing just part of a lead line can actually make lead exposure worse.

Last January, engineers from Virginia Tech, published their findings from a four-year simulation study that looked at the long-term impact of partial lead line replacements on drinking water.

Under moderate and high water flow rates, pipe containing lead and copper released considerably more lead into the water supply than pipes made from lead alone.

The research, co-authored by Marc Edwards, a professor at Virginia Tech who helped uncover the cause of the Flint water crisis, assessed the impacts of three different water service lines:

• Using 100 percent lead throughout.
• Partially replacing half the copper upstream from the remaining lead pipe (this is the conventional method).
• Partially replacing half the lead upstream from the remaining copper pipe.

Elevated lead from corrosion worsened over time for the 50 percent copper configurations with 140 percent more lead released at 14 months. At high flow rates, all of the samples collected from the conventional partial configuration exceeded health safety thresholds, compared to none for samples collected from 100 percent lead pipe.

It all comes down to a natural enemy of metals — corrosion. All metals corrode when exposed to water and oxygen. It’s just a matter of time. But the process accelerates when two different metals are joined together. As a result, “galvanic” corrosion effectively produces an unfortunate battery of sorts with electrons moving from one metal to the other through the conductive water. Over time, this breaks down one metal at the expense of the other. And in a battle between lead and copper, lead is always the loser.

Big picture

Michigan legislators, of course, aren’t alone in picking through a host of issues since ownership of drinking water service lines is split between public water agencies with access to public funds and a lot of private property owners with access to none.

Let’s review, in particular the lead issue, from the top down.

The Safe Drinking Water Act gives the EPA federal authority to set drinking water standards. Most potential contaminants are regulated by limiting their amount in drinking water.

This approach specifies maximum contaminant levels allowable in treated water, and compliance is solely under the control of municipalities because municipalities have direct control over the sources of contaminants through local treatment, storage and distribution.

Current interpretations of state laws, however, often prohibit water municipalities from spending municipal resources on private plumbing, thereby limiting their abilities to replace lead sources on private property.

Within this constraint, the EPA enacted the afore-mentioned Lead and Copper Rule to prioritize monitoring, customer notification, and select municipal interventions that are designed to reduce the public’s exposure to lead in drinking water.

The Lead and Copper Rule, which has been undergoing a re-write for over a year and may get an update this year, requires drinking water agencies to annually monitor the amount of lead at their customers’ faucets. Water agencies are required to prioritize sampling water in homes more likely to have lead. If more than 10 percent of these samples exceed the action level, municipalities are required to notify and educate customers, attempt water treatment techniques that may reduce lead leaching into drinking water, and monitor both drinking water supplies and lead at customers’ faucets.

If ongoing monitoring demonstrates that more than 10 percent of customers continue to exceed the action level, water agencies are required to annually replace 7 percent of publically owned lead service laterals until monitoring indicates lead sampled at customers’ faucets falls below the action level.

Ground level

Finally, at the literal ground level, finding these decades-old lead service lead lines is a big problem. Records describing the installation were probably scribbled down on pencil on an index card and filed away akin to an old-school library card catalog.

When water agencies do initiate a lead line replacement, EPA rules require the agencies to notify customers and provide them with ample time to coordinate replacing the privately owned portion, if they wish.

But digging up a lawn and landscaping just to have a new water line buried beneath the front yard isn’t on many people’s wish list. It’s no surprise that most property owners opt not to replace their portion of lead lines when given the choice.

While a partial line replacement remains common practice, at least one Michigan town we read about is replacing the entire lead service lines.

In Grand Rapids, city officials decided it was worth it for the city to cover the costs of full lead line replacements.

Homeowners aren’t likely to balk when the replacement cost is one number. To date, Grand Rapids says it has spent about a half a million dollars in public funds to replace more than 200 private lead lines. Only one homeowner refused. (And for the time being, we’ll set aside the whole matter of public funds paying the full freight. For more, see “Free Lunch, No Such Thing As.”)

In Dearborn, however, the city is still sticking with partial lead replacements, but implementing a robust program, featuring ads and social media, to warn residents what they are getting or, rather, not getting. The program also includes sampling water before and after the work, recurring water flushing as well as free bottled water.

Meanwhile at the state level, Synder has said he would implement some of his plans through administrative rule making, while others would need legislative approval.

Oswald said banning partial replacements is "not feasible" due to property rights issues, but he added there would be "very tight controls" if a homeowner refuses to let a lead line be fully replaced.