Exempt Wells

Exempt Wells: A bum deal for Montana’s rivers

For many years in Montana, small individual wells have been exempt from any regulatory oversight. The law originally intended permit-exempt wells to be used on an individual basis, trusting that a single well would not have many negative impacts on nearby water users. In the late 1990s and 2000s, however, developers found the loophole and started using the permit-exempt well rule for each ‘individual’ home they build. That means they drill dozens, in some cases hundreds, of exempt wells in subdivisions across the state rather than applying for a new water use permit through the DNRC.

Individual wells can cause a steady lowering of the water table that can reduce flow in nearby creeks, and reduce available water even for those with senior water rights.

When a new subdivision is built, part of the old process (pre-1993) was to obtain a study showing the water-use impact a subdivision would have on neighboring waterways, water right holders, and the groundwater. If a proposed subdivision was shown to have a negative impact, water use permits were denied and the subdivision could not be constructed as originally planned. After 1993, using the permit-exempt well loophole meant developers could build countless homes without a water-use impact study.

On average, 3 of every 4 new homes built in Montana during the last decade use individual wells and septics. Those are like “straws” punched into the ground that then pull out water without the oversight to make sure the water is physically and legally available. This unrestricted use of water can negatively impact permitted water right holders and harm groundwater levels and streamflows. In addition, the septics that usually go along with these exempt wells increase the nutrient pollution in our waterways.

DNRC recognized several years ago that their 1993 rule is being gamed, and noted that—as more basins are closed to new water users—there will be more people attempting to use this provision in new and creative ways that are not consistent with the purpose of the MT Water Use law.

Upshot: this exempt wells rule has been litigated and declared invalid. However, that hasn’t stopped some legislators from trying to re-open this problematic loophole in the 2017 and 2019 legislative sessions, and likely in the 2021 session as well. We are tracking developments closely and will update this page with additional information and talking points in the near future.


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