But waste leaking from an aging home septic system?
That, says University of New Mexico engineering professor Bruce Thomson, is precisely the problem.
“It’s groundwater contamination that’s happening all around us, and we’re not paying any attention,” said Thomson, an expert in treating human waste who delights in describing his academic specialty as “turd mechanics.”
Septic systems drain away household waste into settling tanks, with the water spilling out into drain fields and the natural filtration of the soil doing the cleanup work. But when they don’t work – because homes are packed too closely together, or the systems are old or poorly maintained, contamination can result. The key problem is nitrates, which can render water dangerous to infants.
“Nitrate contamination from leaking septic systems is a problem statewide, and here in Bernalillo County, and it’s contamination that’s entirely preventable,” said Bernalillo County Commissioner Maggie Hart Stebbins.
This evening, the Bernalillo County Commission will take a fresh stab at tightening the rules to try to reduce the risk, a combination of inspections of aging systems and rules that push some septic system owners to hook up to the region’s municipal sewer system if that is an option.
As currently proposed, the ordinance would:
- Mandate regular inspections of septic systems 30 years and older, with upgrades required if the system is failing.
- Require residents of homes on septic systems 30 years or older to connect to municipal sewer lines if one is available.
The ordinance, pushed by Hart Stebbins, has been bouncing around for more than a year, delayed by opponents’ concerns because of the way the cost of compliance falls on homeowners.
The Carnuel neighborhood, located in Tijeras Canyon, is a good example of the problem that septic systems can cause. Homes in the area depend on wells for their water and use septic tanks to dispose of their waste. Measurements of water quality taken in the area show the problem, Thomson said. The higher up the hill you are, the lower the levels of nitrates. But for residents downstream from the clusters of septic systems, the contamination from uphill neighbors has left well water of questionable quality.
It’s a classic example of what economists would call an “externality” – when the actions of one person impose costs on someone else.
“You have an area where the groundwater is essentially undrinkable because of contamination from septic systems,” Hart Stebbins said of Carnuel. When that happens, taxpayers are often on the hook for coming in and helping fix the problem by providing piped-in clean water. That is what is happening in Carnuel, where the Albuquerque Bernalillo County Water Utility Authority is now building a water distribution system extension to serve the community.
Last Wednesday, the water utility’s board of directors approved the use of $2 million in state capital improvement funds to help build that system.
The ordinance change has been a long time coming, with opposition from some residents of areas that could be affected concerned about the costs. “In principle, I agree that failed systems need to be fixed, but I think great care should be taken not to make criminals out of homeowners who are generally good citizens,” said Chris Bettman, who lives in the Sandia Knolls neighborhood in the county’s East Mountains.
Bettman said he is concerned that the data on which the county’s new ordinance is based do not sufficiently link overall contamination problems to the failure of individual systems, and that the resulting costs to homeowners could be onerous.
Those costs could be substantial. According to county data, connecting to a nearby sewer line could cost as much as $5,000. The cost of upgrading septic systems when no sewer line is available could cost anywhere from $3,000 to $15,000.
Hart Stebbins argued that is fair, because one of the costs of home ownership is “responsible disposal of wastewater.”
She also noted that the community’s experience with the massive Kirtland Air Force fuel spill, which has contaminated groundwater beneath southeast Albuquerque and could cost $100 million to clean up, suggests the advantage of cutting off contamination before it starts.
“If there’s one thing we’ve learned from the Kirtland jet fuel spill,” Hart Stebbins said, “it’s much more cost-effective to prevent than remediate.”