Water flows through a pre-sedimentation staging center at the Fargo Water Treatment Plant in south Fargo. Photos by David Samson / Forum Communications Co.
Marino Eccher - Reporter - The Forum
The goal of water treatment is perfection, and the people who do the job work around the clock to wring the impurities from every last drop. But it doesn’t always work out that way.
Drinking water can contain trace amounts of everything from the metals in pipes to leftover disinfectant chemicals to radioactive materials.
Unless something goes very wrong, it isn’t enough to hurt you. The most recent contaminant tests for Fargo, Moorhead and Grand Forks tap water all fell within acceptable Environmental Protection Agency limits. Usually, it isn’t even enough for you to know it’s there – no more than a few parts in a million or a billion.
The EPA requires monitoring of more than 80 potential drinking water contaminants. Most of those never show up in regional tap water testing. Here’s a rundown of a few common ones that do:
Keith Ward monitors the control systems, such as the water tower levels, at the Fargo Water Treatment Plant. Ward is one of 10 operators who work in the control center in south Fargo. David Samson / The Forum
Organic carbons
These come from broken-down plants and other organic materials that decompose in or near water sources. In treated water in the region, they’re typically detected in the range of four to eight parts per million.
Organic carbons are one of the primary causes of taste and odor issues in water. They can be especially pernicious to treat because some people are sensitive to their effects even in the parts- per-billion range. It’s difficult to scrub water of particles that small.
The Fargo and Moorhead treatment plants use ozone disinfection because it’s an effective way of breaking down taste- and odor-causing organics. Before that, spring runoff of dead vegetation regularly brought taste and odor complaints.
Grand Forks, which uses chlorine, is considering making a similar switch at its next upgrade.
Water is filtered through different types of media in the final stages of the treatment process at the Fargo plant. Each of the six basins handle 5 million gallons of water per day. David Samson / The Forum
Nitrates and arsenic
High-nitrogen fertilizers produce nitrate runoff. Nitrates can also come from septic tanks and sewage, and from natural erosion. Nitrates generally are not considered dangerous to most people, but are potentially harmful to infants at higher doses.
The EPA requires no more than 10 parts per million. Fargo water last tested at 1.1 parts per million, and Moorhead and Grand Forks were comfortably below that.
Arsenic, meanwhile, comes from natural deposits, waste from some production processes, and some pesticides. It is a potent toxin, and is measured in parts per billion.
Fargo’s most recent water report showed no arsenic. Moorhead water showed 1.2 parts per billion, while Grand Forks water showed about the same level. Both are well below the EPA threshold of 10 parts per billion.
One of the secondary softening basins at the Fargo plant. David Samson / The Forum
Bacteria
Coliform bacteria sometimes occur in drinking water. Rather than parts per million or billion, bacteria in drinking water is measured in positive tests of monthly samples.
A positive test does not necessarily mean harmful bacteria are present, but it does trigger extensive follow-up testing to be sure.
The EPA requires positive tests in no more than 5 percent of monthly samples.
Fargo and Grand Forks both had the occasional positive test, but were well below that guideline. Bacteria was not a factor in Moorhead’s latest report.
Ozone generators convert oxygen to ozone that is added to water for disinfection. David Samson / The Forum
Disinfectants and additives
Chlorine disinfection produces byproducts that can be harmful in sufficient doses. These are measured in parts per billion, and regional water treatment plants all measure below EPA thresholds.
Tap water also contains a few parts per million of chloramine, the disinfectant added to keep water clean while it travels from the treatment plant to users.
Fargo, Moorhead, and Grand Forks all add about 1.2 parts per million of fluoride to drinking water for dental health.
Large transfer pumps move water to the storage reservoir at the Fargo Water Treatment Plant. David Samson / The Forum
Residue from plumbing
Tap water sometimes contains small amounts of copper or lead. That comes from corrosion of pipes and plumbing. In fact, treatment processes leave some hardness-causing minerals from water because those minerals create a protective film on the insides of pipes.
Overly soft water is corrosive to exposed metal.
Elevated levels of lead can be hazardous to some people, especially pregnant women and young children. To minimize exposure, treatment experts recommend running the tap until the water turns cold to ensure to flush out water that’s been sitting in the pipes.
Other contaminants
For monitoring and data collection purposes, treatment facilities test for a number of contaminants that are not regulated by the EPA. These include iron, nickel, calcium, magnesium, sodium, and sulfate. They sometimes appear in drinking water in amounts ranging from a fraction of one part per million to a few hundred parts per million. There are no current EPA standards for these contaminants.
Drinking water can also contain small amounts of soil runoff, measured by the cloudiness of the water. This measure is known as turbidity. It has no health effects, but can interfere with disinfection and aid microbial growth.
Water By The Numbers
Snapshot of area municipalities that made their data available on things such as capacity, budgets and even how much sludge is produced
Fargo
Customers served: 27,752 water service connections (about 105,000 residents)
Annual operating cost: About $6.2 million
Maximum daily capacity: 30 million gallons
Average daily output: 11 million gallons
Annual output: 4 billion gallons
Annual byproduct sludge: About 32,000 tons
Grand Forks
Customers served: 14,100 meters (about 53,000 residents)
Annual operating cost: $3.8 million
Maximum daily capacity: 16.5 million gallons
Average daily output (gallons): 8 million gallons
Annual output: About 2.9 billion gallons
Annual byproduct (sludge): About 7,500 tons per year
Detroit Lakes, Minn.
Customers served: 4,000
Annual operating cost: $105,000
Maximum daily capacity: 4 million gallons
Average daily output: 1.2 million gallons
Annual output: 370 million gallons
Annual byproduct (sludge): 7 million gallons per year of iron residual
Marino Eccher reports for The Forum of Fargo-Moorhead
