PUEBLO COUNTY, Colo. -

A ruling Tuesday by the U.S. Bureau of Reclamation has marijuana growers fearing that their new businesses will dry up due to lack of water.

The bureau said local water districts that use federally-managed water cannot sell that water to legalized marijuana growing operations, and that anyone suspected of doing so will be reported to the U.S. Department of Justice for prosecution.

The ruling addresses some -- but not all -- of the questions from water districts concerned about breaking federal law since marijuana remains illegal at the federal level.

Two months ago, the St. Charles Mesa Water District issued a moratorium on supplying marijuana businesses, partly in anticipation of the bureau's ruling.  David Simpson, the district's general manager, said the moratorium was to protect growers as well as his own district.

"What if we had to cut them off after they already built greenhouses and had product growing?"  he said.  "Whose responsibility is that?  We really are looking out for the growers, though they may not believe it."

Simpson said he wants the bureau to clarify its ruling before he decides if further action is necessary.  He particularly wants to know if the ruling will affect how districts manage water during a drought.

Jack Johnston of Pueblo West Water said the ruling is too ambiguous.  He plans to continue supplying water to two growing operations until his questions are answered.

The ruling came a few hours before the Pueblo Board of Water Works was to decide whether to provide water to future growing operations within the city limits.  The city council is scheduled to begin approving licenses next month.  The board decided to delay a decision.

"That information was just too much in too short a time period to come up with a hasty decision," said PBWW spokesman Paul Fanning.  "This is new territory for everyone.  I know there's an expectation that we'll provide water, but we first need to make sure there are no legal problems with that."

The bureau describes the ruling a "temporary policy" that could change if the federal government's stance on marijuana changes. 

According to the ruling, only "project" water -- that owned or managed by the bureau -- is affected.  Water that is owned by water districts but flows through federal facilities, known as "co-mingling" water, is not included in the ruling. 

Several water districts expressed concern about whether including co-mingling water would limit their ability to properly manage their districts and meet the needs of other commercial and residential users.

According to records obtained from the Pueblo County Clerk's Office, there are seven marijuana growers licensed, three approved and awaiting licenses, and one applying for a license.