A hold on new proposed subdivisions that would use septic tanks in Tooele Valley has been extended to May.
The Tooele County Board of Health voted to extend the hold during their meeting Tuesday, after viewing preliminary results of a septic tank density study prepared by a Midvale-based engineering firm.
Board members also voted in support of county health department director Jeff Coombs’ recommendations to table further action until staff have reviewed the study data and to hold a public meeting to present the study’s findings. No date has been set for the meeting yet.
“We’re still reviewing the study, to dissect what it means and how it will affect policy,” Coombs said.
Board members are also planning to discuss the study with Stansbury Park Improvement District and other local city governments before making policy decisions, he added.
Tooele County contracted Hansen, Allen & Luce, Inc. to perform the study of Tooele Valley in January. The study’s purpose is to provide up-to-date information about how the current number of septic tanks in the valley could be affecting groundwater and the quality of drinking water. The information will then be used to create a master plan to protect the valley’s groundwater as population grows, according to the engineers’ presentation Tuesday.
Groundwater quality has degraded somewhat since the last study conducted by the Utah Geological Survey in 1998, according to the engineers’ preliminary data.
The engineers used nitrate levels to judge water quality. Nitrate levels should not exceed 10 milligrams per liter of water, according to the Environmental Protection Agency’s standards for drinking water.
At the time of the 1998 study, the average level of nitrates in Tooele Valley was between 2 and 2.5 milligrams per liter of water, Coombs said.
Currently, the average level of nitrates in Tooele Valley is between 3 and 3.5 milligrams of nitrate per liter of water. In some areas, where there are multiple septic tanks close together, the nitrate level is higher, according to the new study.
But although nitrate levels have increased in the past 18 years, the quality of valley drinking water is still good, Coombs said.
“We don’t want to panic people, but we do want people to be aware,” he said. “The whole point of this study is so we can head this off before it becomes a big problem.”
Nitrate is a pollutant that typically comes from fertilizer use, traditional septic tank soil-absorption systems, sewage and erosion of natural deposits. Drinking water that contains more than 10 milligrams of nitrate per liter of water can cause infants to become ill, such as with blue-baby syndrome, according to the EPA.