A Deep Dive Into Cambridge Water

waterAll illustrations by Stefan Mallette.

Local Water Proves Problematic For Coffee Shops

Shortly after Justin Pronovost launched Curio Coffee, he started having severe problems with his equipment.

He soon found out that the city’s water was to blame.

“We had a very basic water filtration system, and after our first two or three months it completely clogged, and we knew we had a water problem,” he says. “We consulted the company we bought the filter from and then the guy said, ‘Oh yeah, I’m pretty knowledgeable about Cambridge water, and you guys have what we consider to be the worst water in the country for filtration purposes.’”

Cambridge’s water may be safe to drink, but its near-limit-pushing levels of chlorides and dissolved solids, its hardness, and its pH pose real problems for the coffee shops that depend on large volumes of water every day. The complicated water is a well-known issue in industry circles, but largely unheard of outside of them.

“It was a challenge, because starting a business is hard enough,” Pronovost says. “It was a hassle, we were fumbling through different systems and their capabilities, we ran out of water some days. It was probably our biggest struggle the first couple of years.”

After more than two years, “many thousands” of dollars, and about eight different filtration systems, earlier this year Curio Coffee settled on reverse osmosis, an intense water purification system that removes essentially everything from water and then requires re-mineralization.

Cambridge’s filtered water contains 236 parts per million (ppm) of chloride, just below the highest level allowed­—250 ppm—according to the 2017 Annual Drinking Water Quality Report. For comparison, as of August 2018 the Massachusetts Water Resources Authority (MWRA), which services the majority of Greater Boston including Somerville, Boston, and Arlington, reports 32.5 ppm of chloride in its tap water.

“Chloride (Cl-), which is a negative ion of chlorine, is a very nasty element, since it speeds up and aggravates the natural phenomenon of corrosion in almost all metals and alloys,” Enrico Wurm, water expert for espresso and coffee machine company La Marzocco, tells Scout in an email.

“When the water is very aggressive and corrosive (high in salinity) … serious pitting corrosion phenomena start,” he continues. “Corrosion then is further boosted by high turbulence, pressure (130 psi) and temperature (around 200 degrees F) present in espresso machines.”

Cambridge owes its high chloride levels in large part to Route 128, which cuts through its water supply, according to Managing Director of the Cambridge Water Department Sam Corda. Despite framing the water as “pretty typical for Eastern Mass.,” Corda acknowledges the striking chloride levels.

“We have higher chlorides than we’d like to have,” he says. “Salt is one of the chloride components, and since the highway is in the middle of our reservoir system and watershed, obviously that’s a contributor. In the wintertime, you salt the roads because you want to get rid of the ice. So road salt is one of the bigger contributors, even though we’ve worked with MassDOT and they do the best they can, but from a safety perspective, they do need to salt the roads.”

“I don’t think it’s a health issue, I don’t think it creates any regulatory issues from a water quality perspective, but the fact that the chlorides have been increasing is a negative, obviously,” he adds.

The chlorides can leave coffee shop owners with ruined equipment that their warranties don’t cover, Pronovost and Broadsheet Coffee Roasters owner Aaron MacDougall explain.

“There are coffee equipment manufacturers that will not honor their warranties in the City of Cambridge unless you have a reverse osmosis system in place,” MacDougall says. “At the equipment manufacturer level, it’s very well known that Cambridge water is problematic for things like hot water towers.”

La Marzocco outlines acceptable ranges for water characteristics in its warranty. The maximum chloride level for the warranty is 30 ppm.

Cimbali, another coffee machine manufacturer, also sets water quality limits within its warranty, according to Sales Director Laurel Bird. “It’s kind of like smoking … it’s all over bad for the machine,” she says of using inadequate water.

At a pH of nine, Cambridge is also outside of La Marzocco’s warranty limits for basicity. The water department increases the pH level for safety reasons, in order to prevent remaining lead and copper pipes and faucets from leaching into the water.

Corda explains that the water’s hardness, which describes how high its levels of calcium and magnesium are, can also damage or clog some equipment. Hard water might leave a white residue on dishes and other items that come into regular contact with the water, according to the department’s website. Cambridge teeters between “slightly hard” and “moderately hard” at 50 to 70 ppm, with the line at 60 ppm, the website explains, adding that water doesn’t need to be softened unless it reaches more than 150 ppm.

The city’s staggering total dissolved solids count of 472 ppm—just below the 500 ppm limit, compared to the MWRA’s tap water’s 135 ppm—also poses a taste issue for coffee shops.

“What’s in the water really impacts how a steeped beverage like coffee tastes,” MacDougall says. “First is how effective the water is as a solvent. Coffee’s all about taking the delicious portion that is extractable out of the coffee and getting it into your cup, and the effectiveness of water as a solvent is a function of many things … It’s a function of how much other dissolved solids reside within the water … If you are trying to brew coffee with water from your tap, chances are you will come out with very under-extracted coffee, [which] tastes sour and astringent.”

But MacDougall, who knew about Cambridge’s challenging water before opening Broadsheet Coffee Roasters, is careful to acknowledge the city’s work.

“There’s no question that Cambridge’s water department is producing water that’s potable … Cambridge is a great city, and the water has its quirks, so I’ve adapted,” he says. “I spend a lot of money on water filtration, it’s an ongoing expense for me … I just said ‘OK, I’m going to spend some money.’ It is what it is, so this is how I deal with it.”

Chlorides also represent a threat to taste, Wurm says.

“Several studies also demonstrate that chlorides increase the solubility (thus boosting the extraction) of very bitter aromatic compounds present in the coffee, making espresso taste quite unpleasant,” he explains.

Corda says he has not heard of any coffee shop or restaurant owners who have contacted the department with issues pertaining to chlorides. He is aware of some clogging issues related to the water’s hardness, however, he says.

Pronovost says he didn’t reach out to the department during his many months of system trials because he “didn’t think they would take it very seriously.”

Corda says that a coffee shop or restaurant having to install “a small-scale [reverse osmosis system] isn’t that big of a deal,” explaining that it would be impractical to burden all water users with the additional expense of implementing reverse osmosis as part of the city’s treatment process.

“Obviously if it continues to rise and becomes a regulatory issue, we’ll have to figure it out,” he says of the chloride levels.

Pronovost doesn’t go as far as to say he would’ve opened his business elsewhere if he’d known about the water’s challenges, but he explains it would’ve “made [him] think twice.”

“We all think Cambridge is really ahead of the curve in a lot of ways … you’d think it would be better, for a city that’s really sophisticated and has a good tax base and a lot of award-winning restaurants and businesses,” he says. “You’d think people would demand more.”

This story originally appeared in the Celebrating the Season issue of Scout Cambridge, which is available for free at more than 200 locations throughout the city or by subscription.

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