Wells test higher for nitrates in county

Homeowners on private wells in the vicinity of Winslow Road south of Weiser have been notified of an unexplained increase in nitrate levels in groundwater over the past year.
 Jami Delmore, with the Southwest District Health Department, recently updated county commissioners on results from testing wells in the county. The level of nitrates doubled in two wells and far exceeded the maximum contaminant level for consumption.
 The SWDH sent a letter to more than 95 property owners in the area informing them that nitrate levels in two wells showed “a significant increase.” The wells were already high in nitrates and in prior years had levels of 30-37 milligrams per liter. Earlier this year, they tested at 70-100 mg/L.
 In the letter to area homeowners, the SWDH “strongly recommends” that property owners on wells get their water tested to see if the nitrate level has increased.  
 Homeowners with water treatment systems already in place should get the treated water tested to make sure nitrates are being removed down to a safe level. Some treatment units would have difficulty getting down to safe levels, Delmore said.
 Some homeowners notified by the state health agency were new to the area and were not aware of the nitrate issue with well water, she said.
 Unlike municipal, public water supplies, private household wells in the county are not regulated by the state or any other agency for water quality or contaminants.
 The area of the county south of Weiser has had issues with nitrates in the groundwater for years, but the recent levels pose a greater health risk to humans, pets and livestock. The level of concern for infants who may consume well water is 10 mg per liter and older children and adults the level is 20 mg/liter.
 A variety of sources generate nitrate, such as precipitation, septic sewer systems, plants, waste from animals, nitrogen-based fertilizers, and other organic matter that return nitrate to the soil as it decomposes. Nitrate is the most widespread contaminant in Idaho’s groundwater, according to the Idaho DEQ.

There are also indications that levels of sulfates, sodium and chloride also may have increased in groundwater in the area south of Weiser based on private well tests. Water from household wells may have develped a salty taste and plants irrigated by well water may show poor growth.
 Household wells in the area around Winslow Road south to Airport Road are fairly shallow, tapping groundwater that is only 20 or 30 feet down. Other wells in the nearby Weiser Industrial Park are much deeper and water from those do not show a nitrate problem.
 State health and department of agriculture officials plan to investigate further to see if they can figure out what has caused the level of nitrates to go up and get a better idea of how the groundwater plume is  moving around.
 “We really need a hydrologist to help us understand the problem,” Delmore said.
 A large feedlot that once operated in the area was blamed for contributing to high nitrate levels in the groundwater, but it has been closed for many years and state environmental regulators have determined it no longer contributes to the problem.
 One unproven theory is that the cull onions dumped and then plowed into the ground in the area could have infiltrated to the groundwater through leaching.
 In the winter 2017, unprecedented amounts of snow caused some onion sheds to collapse, ruining onions that then had to be thrown away by the tons.
 Delmore said the state ag department is not willing to change the cull onion disposal regulations without some sort of factual basis that the current practice is causing groundwater issues.
 “We just don’t have enough evidence,” she said.
 The SWDH received approval from county commissioners to do more testing in the area. The health agency also plans to continue with educational outreach about groundwater issues. There is not much the county can do about the nitrate issue.
 A community well and water distribution system to supply homes in the area with water from a deeper source is an idea that would be costly and far into the future.
 Officials said they cannot recommend drilling deep wells that could cost homeowners thousands of dollars and may or may not find better water.
 There are two laboratories in Boise that are certified for testing drinking water – Analytical Laboratories and the Idaho Bureau of Laboratories.
 The SWDH office in Weiser on West Court Street has bottles to collect water. The SWDH charges $10 for the courier service to the IBL in Boise. The lab costs vary depending on what test is ordered.