Email Stay Connected with the Daily Roundup. Sign up for our newsletter and get the best of the Beacon delivered every day to your inbox. BILLINGS – Montana officials said Wednesday they will rewrite a rule that allowed tens of thousands of rural homes to be built without water permits, but it was unclear what impact the proposal would have on development.Rural homes can be built in Montana without a water permit if they have their own well. But ranchers and conservation groups say aquifers can be strained beyond capacity by such exemptions.There’s no limit on how many exemptions can be issued, and more than 70,000 have been granted for new homes in the last four decades.The Department of Natural Resources and Conservation ruled Wednesday to repeal the exemption in coming months. A tentative replacement would limit the number of well exemptions allowed for a single project or subdivision to 12.DNRC water resources division administrator Tom Schultz said that would encourage builders to construct projects of 12 homes or fewer in rural areas.“Over time, you could expect development patterns to shift,” he said.Yet critics said developers could build 12 homes one year, then come back the next year to build 12 more, and so on into the future.“That’s a change on paper and not a change in practice,” said Laura Ziemer with Trout Unlimited’s Montana Water Project.Dustin Stewart, with the Montana Building Industry Association, said Wednesday’s ruling was a “small victory” because it preserved the idea of water-permit exemptions for rural subdivisions.Without the exemptions, Stewart’s group said the cost of attaining water permits could limit development.The proposed cap of 12 exempt homes per subdivision is more restrictive than current rules, but Stewart said the number was “arbitrary” and likely to change before a final rule is adopted.The DNRC will begin formulating the new rule within eight months. It could be an additional six months before it is final, said Schultz.