Geosmin. It’s that earthy smell just after a rainstorm, the dirt flavor in beet peels and, recently, the odor and taste in Cañon City’s municipal water.

“The water’s changed recently,” resident Heather Wilkerson told the City Council this week.

Residents packed council chambers seeking answers about what several described as a swampy turn in the water coming out of their taps. Residents started noticing something off about two weeks ago, said Mayor Phil Lund.

Tests of municipal water have not turned up anything alarming, according to Water Superintendent Travis Payne. At 20 sites across the city, regular bacterial testing has shown results within norms set by the Colorado Department of Public Health and Environment. Levels of chlorine in the water — a main treatment chemical — are also good.

Barring bacterial contamination, city water officials sent samples to a lab in Texas to determine what could be causing changes in the taste and odor of the water. Enter geosmin.

Geosmin is an organic chemical compound produced by bacteria and algae. It’s literally translated “earth smell,” and is the main reason a handful of fresh-turned soil smells the way it does. Unfortunately, the presence of geosmin in drinking water is not as pleasant to the senses; it’s a major cause of complaints even in very small quantities.

The Texas lab found a tiny quantity of geosmin in Cañon City’s water — the highest system measurement was 690 nanograms per liter. A nanogram is one billionth of a gram, analogous to a drop of water in a lake. Payne said the amount was not a public safety risk.

Still, humans are amazing at detecting geosmin. People can taste and smell the compound at as little as 5 nanograms per liter. The funky water in Cañon City, while not a health risk, has been affecting residents’ peace of mind and the bottom line of local businesses.

Heather Peterson, who works in the bar and service industry in Cañon City, told the council that out-of-town customers were asking questions.

“It is kind of like making excuses for someone you like when something isn’t quite right,” she said.

In a Facebook post this week, the Whitewater Bar and Grill told customers it had installed a commercial filtration system. Its rooftop bar was in the process of installing the same system; in the meantime, water bottles were $1.

“Come taste the difference,” the post reads.

Payne said the concentration of geosmin is probably an indirect result of regional drought: low flow and warm water in the city’s reservoir likely bred conditions for the chemical to build up. In response, the city has coated its reservoir with copper sulphate, increased chlorine treatment and pushed fresher water through its distribution system. Tests are out now for analysis on whether there have been improvements, said Payne.

Without a genuine risk to public health, Payne said the city was trying not to go overboard with its response.

“We’re not going to overreact to this,” he said.

While more regular hydrant flushing might have improved the problem, he said the city also needed to keep water conservation in mind. The Arkansas River, which supplies the town, has been close to a river call this summer that would force the town to use its reserves.

Water rights in Colorado work on a “first in time, first in right” policy, wherein the holders of older rights have seniority over younger rights. If a senior right holder is not getting their full water allotment, the state can implement a river call to cut off junior right holders. Payne said Cañon City’s water right was established in 1863. This year, rights have been called back to 1867.

Things are improving slightly; still, he said the city needs to be cautious about its water use. Voluntary water restrictions have been in place since July 1.

“Until we get a good snowpack, we’re not going to be good for all summer,” he said.

In the meantime, the city recommends that residents use activated carbon filters.

“There are significant things that happen in the environment that we just don’t have control over,” said Cañon City Councilmember Fred Toney.