Water contamination in Exeter critical but fixable

Last week, an official and dire-sounding warning about high nitrate levels in the city of Exeter’s water supply began appearing on social media sites, and with them came comments rife with speculation, fearful reactions and visions of impending doom. The water situation in the midsize foothill town, however, is not as dangerous or widespread as some of those who stumble across the notice without context imagine it is.

The city-issued caution can be read at cityofexeter.com/drinking-water-warning/.


Exeter’s Water Safe for Most

The reality, says Exeter’s Director of Public Works Daymon Qualls, is Exeter’s water remains safe for most consumers. It should not be consumed by infants and pregnant women until the nitrate levels drop, probably in the autumn when the dry season ends. The city will alert users when that happens.

The reason most Exeter residents can still draw safe water from their taps without excess worry right now has to do with how the city’s water system combines the output of all the city’s wells.

“Exeter has a loop water distribution system,” Qualls said via email. “Because all the water lines in the streets are connected, the water is blended. Only one well has nitrates at one part per million over the maximum contaminant level, and this well only produces water when there is a large demand on the water system.”

The contaminated well, known as E6-W, cannot be taken offline now, or the city would run shy of water to meet businesses and residents’ needs. To compensate for its contamination, E6-W is being left out of the loop as much as possible.

“Because of operational changes we have made, this well has been running approximately two hours per day,” Qualls wrote. “This water is blended with water from other wells which reduces the concentration.  We still encourage women that are pregnant or nursing, and children younger than 6-months-old to drink bottled water.”


Nitrates Can Kill

According to the drinking water warning issued by the city on May 13 and available via the city’s website, staff at Public Works became aware of the issue when samples from two days earlier returned unacceptable results. The notice’s opening line made the danger to consumers clear:

“Water sample results received (May 11, 2022) showed nitrate levels of 11 milligrams per liter. This is above the nitrate standard, or maximum contaminant level (MCL), of 10 milligrams per liter.  Nitrate in drinking water is a serious health concern for infants less than six months old.”

While the good news is the city’s single heavily contaminated well is testing barely above the state’s standard for safety, it can still prove harmful to a small at-risk population. Nitrates can hamper the body’s ability to carry oxygen via the bloodstream, and in infants this can lead to serious illness and death. The same is true for pregnant women and those nursing infants.

Symptoms of nitrate poisoning include blue skin and shortness of breath. Anyone displaying these symptoms should immediately seek medical care.

For now, Exeter’s water should not be given to infants or used by pregnant women, but it should also not be used for mixing baby feeding formulas or juices for small children. Boiling the water can make the problem worse by concentrating the nitrates. Those with other health issues who are concerned about the effects of high nitrates should consult their medical providers.


Drought Makes Contamination Worse

The city is also asking residents to conserve water wherever and whenever possible. Just as boiling the contaminated water will drive off the water and leave behind the nitrates, so too will dropping the local water table to even deeper depths. As the state’s worst recorded drought forces farmers and water suppliers to draw ever more groundwater, they also make the nitrates more intense in all local wells.

Nitrates are a class of run-off contaminants that comes from a variety of sources, like industry, and agriculture, as well as naturally occurring ones. They also leech into the water supply from septic systems and storm drains, and from areas fertilized for ag and landscaping use.

Another good bit of news is nitrate plumes move fairly quickly below ground, meaning once sources of runoff are identified, they can be removed and well eventually remediated.

“It is impossible to stop nitrate infiltration,” Qualls said. “Nitrates move through the ground and eventually reach the water table. The removal process is an ongoing and relatively expensive process. The most common treatment methods are ion exchange, distillation and reverse osmosis.”


Fixing It Now and Fixing It Later

More good news: The contamination shouldn’t spread.

“Based on historical test results, we do not expect any other wells to be impacted,” Qualls wrote. “Nitrates move through the ground relatively fast and cannot be stopped.”

Exeter officials have the problem in hand, with a firm plan for eliminating the contamination from the city supply quickly as possible.

“Our long-term plan is to add additional wells to the system,” Qualls wrote. “In the short term, we are completing repairs on Well E9-W, which is currently offline, and hope to have it producing water sometime in July. Rehabilitation of another well is on hold until the aforementioned well is back in service.”

When that happens, the contaminated well will go offline for good.

“Once other sources are activated or rehabilitated, Well E6-W will be placed in a stand-by condition,” according to Qualls. “That means it will only be used in case of an extreme emergency, such as a large fire.”


The Tooleville Water Problem

Despite having a fix for its own water worries, Exeter is still being forced by the state to enlarge its water works to include the 79 residents that make up the tiny community of Tooleville, just east of Exeter in the orange orchards spreading south along Spruce Avenue.

Residents in Tooleville have been on a quest for safe drinking water for decades. Finally, in the summer of 2021, another remarkably hot and dry season, the California Division of Drinking Water mandated the cooperation of Exeter in supplying water to its smaller neighbor. The cities were given six months to reach an agreement or faced having the state impose itself.

Now, three months after that deadline elapsed, the state has backed off in light of Exeter’s new worry woes. During a public hearing on the issue last month, a representative of the state told those on hand the issue of folding Tooleville into Exeter’s water system would not be realized until 2030 at the earliest.

But the residents of Tooleville need safe, clean water in their homes, so talks between the two communities’ representatives goes on.

“The city of Exeter and Tooleville are still in negotiations regarding a potential connection to serve the residents of Tooleville, and the state is receiving regular updates on our progress,” Qualls wrote. “It is understood by all parties that Exeter’s water system, in its current condition, does not have sufficient capacity to support a connection at this time.”

For more information on Exeter’s water issues, contact Public Works at (559) 592-3318, ext. 2.

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