Utah’s water system poses a unique but avoidable risk – if we understand it

Last July, there was an E. coli outbreak in Utah.

I don't know about you, but E. coli is one of those things that I love to laugh about when it's mentioned in the news. The rhythms of the story are now so familiar: At the center of an outbreak is a salad or a restaurant, some people get sick, health authorities intervene, and things return to normal. It's just… predictable.

But last week, the Centers for Disease Control and Prevention released a report on the Utah outbreak in its Morbidity and Mortality Weekly Report – a summary of interesting but damaging events in the United States. Much of what we learned about COVID outbreaks came in the MMWR, for example.

This report fell outside the usual E. coli story. Rather than ending with a tidy bow, this report highlights some ongoing risks that I think many Utahns want to know about.

In particular, Utah's unique water supply system poses some danger. Let me explain.

What happened in Utah?

Last summer, between July 22 and 27, six children in Lehi tested positive for E. coli. This is unusual, of course, so they tested the children's E. coli strains and found that they were exactly the same. In other words, their illness had the same origin.

But when Utah Department of Health experts interviewed the children's parents, there wasn't much in common between the children. They hadn't eaten at the same restaurant or even had the same meals. The only thing they had in common was that they had all recently been playing outside in the water. But of course they had it. They are children.

Yet health authorities had to do just that. So they examined water samples from places where the children had played – particularly in backyards and parks. They found E. coli at five of these locations.

They then tested two of Lehi's water reservoirs and found E. coli in one of them.

The Utah County Health Department issued a press release about the outbreak on August 4; Lehi sent out a notice on Aug. 19 confirming that E. coli had been found. Officials also sent a notice to residents on August 28. On August 31, the last case in the outbreak was discovered.

A total of 13 children were diagnosed with an E. coli infection. The children were between 1 and 15 years old. The average age was 4 years. Five of them had played with Lehi tube water, five with inflatable lawn water toys and water tables. Two remembered drinking the water from the hose, one simply ran through the sprinkler system.

Seven of them were hospitalized, and two of them had “hemolytic uremic syndrome,” which causes smaller blood vessels, a change in skin color and often kidney failure in children. This is relatively common in children, especially if they are infected with E. coli.

But that's not all: While there have been 13 confirmed cases, experts estimate that for every diagnosed case, there are 26.1 undiagnosed cases of E. coli infection in humans. So we can estimate that about 340 people, probably mostly children, got sick with E. coli in Lehi last summer.

Secondary water systems

So what allowed this to happen? Well, Lehi, like many cities in Utah, has a two-track irrigation system. Households use the “primary” drinking water system – the water that is passed through treatment plants to make it safe for human consumption. And “secondary” water is used for outdoor use. This is what the CDC calls “untreated, pressurized municipal irrigation water” — water that flows down from the mountains, stays in reservoirs, and is then piped into backyards. It is clear that E. coli migrated through this latter system.

I spent most of my youth in Riverton, where they have this two-track system. I'll be honest, I thought this was a pretty ubiquitous facility, at least in the suburbs.

But it turns out that these secondary water systems, where the water is untreated but still delivered to homes, are extremely rare outside of Utah. This is common practice across the country on farms and the like, but the fact that Utah communities are sending untreated water to suburban homes, even for outdoor use, came as a surprise to many at the CDC. In most other places that just doesn't happen.

Which communities in Utah have secondary water systems? Here is the map.

(Utah Depratment of Natural Resources) A ​​map of Utah's secondary water suppliers as of May 2024.

(Utah Depratment of Natural Resources) A ​​map of secondary water suppliers along the Wasatch Front as of May 2024.

Cities with secondary water include West Jordan, South Jordan, Riverton, Herriman, Bluffdale, Alpine, Lehi, Pleasant Grove, American Fork, Springville, Spanish Fork, Payson, Grantsville, Stansbury, Park City, Midway, Bountiful, Farmington, Kaysville, Syracuse, Clinton, Roy, North Ogden and many more. As I said, look at the map.

Although it's uncommon outside of Utah, I have to say that secondary water seems to me to be a pretty sensible system most of the time, at least in my opinion. Since most of the water used in residential areas is outdoors, maintaining green lawns by not treating this water saves cities a lot of money, time and effort. This saves water treatment costs in the tens of millions. And it makes sense that these suburbs, which until recently were predominantly agricultural, are simply switching those irrigation systems to lawn irrigation systems.

What should we do?

But every now and then there will be an outbreak like this. UDOH officials couldn't say exactly how many of these had occurred before, but said this mechanism would explain several untraceable past outbreaks in Utah.

E. coli outbreaks usually occur due to feces. To find out where the E. coli came from, UDOH examined Lehi's backyards, parks and reservoirs for traces of various types of feces – from birds, ruminants (cows, sheep, deer, etc.) and humans.

Could you perhaps separate the E. coli contaminated feces from the water sources? Unfortunately, in the places where E. coli tested positive, most of the feces tested negative – with one exception. They all tested positive for bird droppings.

Of course, this is the hardest thing to avoid. Birds constantly fly over all sorts of things and poop in or on them. If a bird picks up an E. coli infection, it's easy to imagine how it could spread to hundreds of children in a community once it settles in the water supply.

The CDC then made some recommendations to communities with secondary water. A logical solution: cover secondary water reservoirs to prevent bird waste from ending up there.

However, their main focus was to make it clear to the public that secondary water is not completely safe when people, and especially children, are involved. They recommended more clearly labeling secondary water systems in public locations, distributing prominent signage for homeowners to use in their yards, and color-coding taps.

In 2022, the Utah legislature passed a law requiring all secondary water systems to be metered by 2030. I wonder if a similar bill could be passed next session to implement some of these recommendations.

I think this would be particularly important given Utah's population growth. Every year, tens of thousands of residents arrive from other states – especially Lehi! The vast majority of them will have never come into contact with secondary water systems.

This does not mean that we should forego secondary water in communities. But it does mean that a good old public information campaign will serve to prevent hundreds of children from getting sick on a regular basis in their own backyard.

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Anna Harden

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