Tony Palumbo's water utility crew had opened a hole 7 feet deep under the sidewalk outside a small rental house in the city's Frogtown neighborhood when their target came into view.
Barely visible among the tangle of roots and dark soil sat an old lead pipe, about as big around as a quarter, one of 14,000 lead service lines the water utility owns. The pipe, likely 100 years old, was in fine shape. But Palumbo's team planned to rip it out anyway, replace it with a copper pipe, and move on to the next one.
Palumbo and his crew are the most visible signs of a decades-long quest in St. Paul to get lead out of the city's drinking water.
In years past, St. Paul struggled mightily to meet federal Environmental Protection Agency standards. The EPA at one point forced the city to remove 7 percent of its lead service lines for three years in a row. But the effort paid off. City lead levels are now below federal limits and officials expect to have the last lead pipes out within 20 years.
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"No one likes to fail," said Jim Bode, who worked in St. Paul's water utility laboratory back when the EPA came down on the city. "Getting served a notice of violation is a failure in our industry. So, yeah, it was stressful."
But Bode, who is now a water quality manager at the plant, said the utility emerged from its lead crisis stronger, and with a key insight: The city needed to treat its water in a way that would create a buffer between lead pipe and water.
At the utility's plant three miles north of downtown St. Paul, murky surface water flows through a series of indoor pools where it is softened, filtered and ultimately treated with sodium hydroxide to raise the water's pH, a measure of its hydrogen ion concentration. Raising the water's pH allows a thin coat of scale to form inside the lead service lines, which prevents the corrosion that leaches lead particles into water.
It took time for St. Paul to perfect its method, but the pH strategy is working well now and is largely responsible for the utility's success in driving down its lead levels to below federal limits.
For all its success, however, St. Paul's system to get the lead out also brings some risk. Ripping out lead pipes beneath the streets can actually raise lead levels in drinking water going into some homes.
That's because St. Paul can only replace the utility-owned segment of a lead service line. The homeowner's portion — the stretch from the sidewalk into the home — may still be lead. Cutting a lead service line can cause flaking in the protective scale lining a lead pipe no matter where the cut occurs. And flaking can last for months.
"In some ways it's a good thing because you're getting some lead out. In some ways it's a bad thing because you could be causing a temporary lead release," said Anna Schliep, a compliance engineer in the Minnesota Department of Health's drinking water protection program.
The St. Paul water utility urges customers to replace their section of pipe at the same time the city replaces its line to the street, but fewer than half do. It can cost a homeowner an average $3,000 to $4,000, said Steve Schneider, general manager for St. Paul Regional Water Services.
"Some people just write the check out," said Schneider. "There are a lot of folks that can't do that, and that is, I think, what most people that are elected officials are struggling with."
To counter those unintended consequences, crews replacing lead pipes have begun handing out water filters and pitchers.
In Frogtown, Tony Palumbo caught Ronald Mendoza as he was taking his two young daughters to school. He gave him a pitcher and filters, explained the potential lead hazard that might exist for a few months and urged him to flush lines and use the filtered water to drink or when cooking.
Despite the risk, the utility is sticking with its replacement plan. If the EPA eventually requires all lead water pipes to be replaced, St. Paul will be ahead of the game, said Bode.
"If you're going to get rid of all the lead line eventually, we have to do our portion of it, right? So there's no sense in delaying that, we feel, as long as we can manage and educate our public and minimize the risk for them," he said.
Minneapolis also has lots of lead service lines and very few of them have been replaced. But lead levels in city water samples are so low, they're barely detectable.
Minneapolis uses a different chemical process from St. Paul that's really effective at building scale on its lines. However, the chemical, called ortho polyphosphate, is also linked to the growth of potentially toxic algal blooms in lakes and rivers. For that reason, some cities have opted not to use it.
Minneapolis' water system also differs from St. Paul's in another key way: Homeowners in Minneapolis own the entire service line. And most don't have a lead problem.
"How do you sell that to a customer and say you gotta pay us $4,000 to remove this because that's just the way it's going to be," said Minneapolis water quality manager George Kraynick.
At this point, he added, replacement doesn't make sense, although he acknowledged that the high-profile crisis in Flint has created additional pressures.
"We know we don't have an issue out there," he said. "So how do you make the pitch to get money to replace these service lines that for all intents and purposes are perfectly fine, until Flint came along. Now they say no level of lead is safe in the water, and things like that."
Most water experts agree Flint will force tougher lead regulations. Whether it's a lower testing threshold, new water treatment requirements or a mandate to remove lead lines altogether, older cities will likely face new expectations and big bills.
Madison, Wis., offers one road map to a lead line fix. The water utility there ordered the removal of all of 8,000 of the city's lead lines over a 10-year period from 2001-2011. It required customers to remove their portion of the line — but offered them $1,000 rebates.
Minneapolis and St. Paul officials aren't talking about that kind of change just yet. But they're keeping a close watch on the national debate over lead and preparing for possible new federal drinking water rules that could come within the year.
Lead in your pipes: What you need to know
The Minnesota Department of Health offers some guidance on lead in water and what you can do to minimize exposure.
Let the water run.
Any time your water pipes have not been used for six hours or longer, run the tap at least two or three minutes. Flushing will safely drain your pipes of water that absorbed lead overnight. After a vacation, flush your water system for twice as long. If you feel like that's wasting water, you can take a shower, flush your toilet, do a load of laundry or water your plants in the morning to clear your pipes.
You can also store a container of freshly collected drinking water in your refrigerator so you don't have to flush your tap multiple times a day.
Don't use hot tap water for drinking or preparing food items such as instant mix cereals.
It is especially important not to use warm or hot water when making baby formula. Hot water dissolves lead more quickly than cold water. Collect cold water and then heat it.
Some water filters also remove lead.
Check the product literature to be sure it has been certified for lead removal by the National Safety Foundation International.
Many water systems and laboratories will test tap water for lead.
Fees vary, but $20 to $30 is a likely range. You can find a list of accredited laboratories on the department website. Just click the "search" button.