FARMINGTON — Preliminary results from an environmental study indicate septic waste may be seeping from sewage systems or being illegally dumped into the Animas and San Juan rivers.

"It is startling. It is unexpected," said David Tomko, San Juan Watershed Group coordinator. "But let's see if there's another explanation."

The environmental group — an offshoot of the U.S. Department of Agriculture — from April to October tested samples of water in the Animas River in Aztec and just north of the Colorado state line. Biologists also collected samples from two sites in Farmington and one west of Waterflow.

The study is the fourth of its kind in New Mexico attempting to identify land use practices that contribute to river contamination.

The Animas, San Juan and La Plata rivers exceed state standards for the E. coli bacteria, Tomko said.

Tests for E. coli in Colorado met that state's and New Mexico's standards, the study found. Tomko said that means E. coli and Bacteroides — both indicators of human and animal waste — originate downstream in San Juan County.

Probes placed at the five sites tested for several species, including humans. While findings for cow and other ruminants are questionable, Tomko's confidence is high for the human results.

All 40 samples collected west of Waterflow tested positive for human bacteria found in feces, according to the study. Nearly all 40 samples collected in Farmington also tested positive, and 26 out of 40 samples collected in Aztec were positive, too, according to the study.

Livestock bacteria levels often rise in rivers in late July, when monsoon rains flush cattle waste down arroyos and into the water, Tomko said. But, he said, human bacteria levels do not follow the rainy season and are likely from another source.

He said septic service businesses have illegally dumped waste before.

In March 2013, Anthony Wiggins, owner of A-1 Septic Services, and Alex Wiggins allegedly unloaded 3,000 gallons of sewage near Bloomfield on Bureau of Land Management land. The estimated cleanup cost was $28,500. The Wiggins brothers were charged with depredation of government property.

Farmington's wastewater treatment plant is the only nearby location to legally discharge sewage. Tomko said businesses could still be dumping elsewhere.

He is cautious, though, to confirm the high test result for human waste. He said only one laboratory has tested the samples, and he wants the opinion of another.

But, he said, the study's findings carry serious implications.

Seven county water systems pull drinking water from one of the three contaminated rivers, according to data complied by Joe Martinez III, a state Environment Department Drinking Water Bureau Public Water System supervision group manager.

"Let me put it this way," Tomko said, "that result has raised red flags in the (Environmental Protection Agency) and (New Mexico) Environment Department."

The San Juan Watershed Group's results also have the attention of the county.

"Certainly that would be a concern for us," Operations Officer Mike Stark said, adding that more than 60 percent of the state's surface water flows though the county.

Stark said county officials are aware illegal septic dumping occurs in the county, and they also know some septic systems are aging and possibly leaking. But the county is large, Stark said, and solutions are expensive.

In early April 2010, El Paso Field Services pipeline workers discovered a colony of 20 trailers abandoned in a box canyon off County Road 3000 and near the Animas River. The community's makeshift septic systems contaminated the soil, Stark said. The trailers were demolished and the land cleaned.

"We've had a couple of situations where people just dug a hole and took the old body of a (Volkswagen) Beetle, turned it upside down and that's their septic tank," Stark said.

Many other septic systems have been illegally and precariously hooked into main sewage lines, he said. He mentioned the Kirtland Lagoon, which was built in 1957 for 25 homes but has since acquired 27 more connections. In the past four winters, it has nearly overflowed twice into the San Juan River.

Regulating the illegal systems is also difficult, Stark said. The environment department staffs 11 full-time employees at its local office, said the department's communication director, Jim Winchester.

Stark said county officials are trying to extend wastewater systems into unincorporated communities. The New Mexico legislature this year allocated $996,000 in capital outlay funds, adding to last year's $2 million capital outlay funding for the project. The project is the top priority on the county's infrastructure capital improvement plan, and it is now fully funded.

Stark said a 3.1-mile long mainline intended to connect as many as 300 Flora Vista residents to Farmington's wastewater treatment plant is fully designed. The $9.1 million needed to complete the project's first phase is the county's second legislative funding priority.

The county has other projects planned, too, he said. But most county residents don't want to pay the costs for the capital projects, he said. And federal and state funds are difficult to acquire for the large projects, he said.

County Executive Officer Kim Carpenter said one of the county's biggest goals is getting residents off septic systems to reduce river pollution.

"These are some serious problems that we have," he said.

Dan Schwartz covers government for The Daily Times. He can be reached at 505-564-4606 and dschwartz@daily-times.com. Follow him @Dan_J_Schwartz on Twitter.