Bloomfield works to lower total trihalomethanes in water

Some test results exceed federal standards

Hannah Grover
Farmington Daily Times
Tony Gonzales, an operator at the city of Bloomfield water treatment plant, checks filters at the plant on Sept. 29, 2016. The city is working to reduce the level of trihalomethanes in a portion of the town's water system.
  • Federal officials say trihalomethanes do not pose immediate threats to health.
  • Public works director Jason Thomas says the levels are decreasing.
  • Several other water systems in the county have also had samples exceed drinking water standards for total trihalomethanes.


FARMINGTON — Bloomfield officials have been working since the spring to address the level of trihalomethanes in a portion of the town's water system, according to public works director Jason Thomas.

According to the New Mexico Environment Department, trihalomethanes form when organic matter mixes with some forms of chlorine. Thomas said the city is adding a chemical to the water that will reduce the amount of organic matter. He said the process could take up to a year to have the desired effect.

A sample site near Western Refining, located off U.S. Highway 550 in north Bloomfield, has produced test results exceeding the level for trihalomethanes that are set by the federal Safe Drinking Water Act. The average level of total trihalomethanes over the last quarter was 87 parts per billion. The drinking water standard is 80 parts per billion or less.

Thomas said a sample taken in November was lower and within U.S. Environmental Protection Agency standards.

"It looks like the readings are starting to trend down," Thomas said, crediting the additives placed in the water for that result.

Bloomfield is also looking into the price of installing an aeration system on a drinking water storage tank on top of the hill off of U.S. Highway 550 in north Bloomfield. Thomas said the aeration system would help lower the trihalomethane level. He said the city would also need to work out the logistics of installing the aeration, including building a power supply to the tank.

"It's no cause for alarm," City Manager Eric Strahl said regarding the level of trihalomethanes. 

The trihalomethanes level does not pose an immediate health risk for drinking water customers, federal officials say. But according to the U.S. Environmental Protection Agency, people who consume excess amounts of trihalomethanes over many years may develop health problems, including an increased risk of cancer.

Bloomfield's water system is one of five drinking water systems in San Juan County that have had total trihalomethane levels exceed drinking water standards over the past couple of months, according to the New Mexico Environment Department's Drinking Water Watch.

The watch also shows total trihalomethane violations for systems serving Blanco, Navajo Dam and the Crouch Mesa area. A system that serves Ignacio, Colo., and a small area of San Juan County also has violated drinking water standards for total trihalomethanes.

During the last federal fiscal year, about 10 water systems serving areas of San Juan County had samples that exceeded standards for total trihalomethanes.

Hannah Grover covers government for The Daily Times. She can be reached at 505-564-4652 or via email at